0001549922-24-000028 | 10-K | XBRL Viewer | Summit Midstream Partners LP

PARTNERS' CAPITAL AND MEZZANINE CAPITAL (Tables)

12 Months Ended

Dec. 31, 2023

An update on the number of common units is as follows for the period from December 31, 2021 to December 31, 2023.


			Common Units
December 31, 2021			7,169,834
2022 Preferred Exchange Offer, net of units withheld for taxes			2,853,875
Common units issued for SMLP LTIP, net			159,054



December 31, 2022			10,182,763

Common units issued for SMLP LTIP, net			193,426

December 31, 2023			10,376,189

A rollforward of the number of outstanding Series A Preferred Units follows for the period from December 31, 2021 to December 31, 2023.


			Series A Preferred Units
December 31, 2021			143,447
2022 Preferred Exchange Offer			(77,939)

December 31, 2022			65,508
2023 activity			—
December 31, 2023			65,508

Schedule of Change in Subsidiary

The following table shows the change in the Partnership’s Subsidiary Series A Preferred Unit balance from January 1, 2022 through December 31, 2023, net of $1.7 million and $2.2 million of unamortized issuance costs at December 31, 2023 and December 31, 2022, respectively:


	(in thousands)
Balance at January 1, 2022	$	106,325

PIK distributions	1,600

Redemption accretion, net of issuance cost amortization	15,544
Cash distribution (includes $1.6 million distributions payable as of December 31, 2022)	(4,885)
Balance at December 31, 2022	$	118,584
Redemption accretion, net of issuance cost amortization	12,581
Cash distribution (includes $1.6 million distributions payable as of December 31, 2023)	(6,513)
Balance at December 31, 2023	$	124,652

LEASES - Future Minimum Lease Payments Due and Future Minimum Rentals to be Received under Noncancelable Leases (Details) $ in Thousands	Dec. 31, 2023 USD ($)
Operating
2024	$ 4,067
2025	3,573
2026	2,468
2027	2,074
2028	61
2029	27
Thereafter	330
Total future minimum lease payments	12,600
Finance
2024	870
2025	736
2026	374
2027	87
2028	0
2029	0
Thereafter	0
Total future minimum lease payments	$ 2,067

FINANCIAL INSTRUMENTS - Fair value of Debt Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Carrying Value \| 2025 Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	$ 49,783	$ 259,463
Carrying Value \| 2026 Secured Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	785,000	785,000
Carrying Value \| 2026 Unsecured Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	209,510	0
Fair Value \| 2025 Senior Notes \| Estimated fair value (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	48,414	221,733
Fair Value \| 2026 Secured Notes \| Estimated fair value (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	778,131	750,983
Fair Value \| 2026 Unsecured Notes \| Estimated fair value (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior notes	$ 203,225	$ 0

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Revenues:
Total revenues	$ 458,903	$ 369,594
Costs and expenses:
Type of Cost, Good or Service [Extensible List]	Natural Gas Liquids [Member]	Natural Gas Liquids [Member]
Cost of natural gas and NGLs	$ 112,462	$ 76,826
Operation and maintenance	100,741	84,152
General and administrative	42,135	44,943
Depreciation and amortization	122,764	119,055
Transaction costs	1,251	6,968
Acquisition integration costs	2,654	0
Gain on asset sales, net	(260)	(507)
Long-lived asset impairment	540	91,644
Total costs and expenses	382,287	423,081
Other income (expense), net	865	(4)
Gain on interest rate swaps	1,830	16,414
Loss on sale of business	(47)	(1,741)
Interest expense	(140,784)	(102,459)
Loss on early extinguishment of debt	(10,934)	0
Loss before income taxes and equity method investment income	(72,454)	(141,277)
Income tax expense	(322)	(325)
Income from equity method investees	33,829	18,141
Net loss	(38,947)	(123,461)
Net loss attributable to Summit Midstream Partners, LP	(51,528)	(140,605)
Parent Company
Costs and expenses:
Add: deemed capital contribution	0	20,974
Series A Preferred Units \| Subsidiary
Costs and expenses:
Less: Net income attributable to Subsidiary Series A Preferred Units	(12,581)	(17,144)
Series A Preferred Units \| Parent Company
Costs and expenses:
Less: Net income attributable to Subsidiary Series A Preferred Units	(11,566)	(8,048)
Common units
Costs and expenses:
Net income (loss) attributable to limited partners	$ (63,094)	$ (127,679)
Net loss per limited partner unit:
Common unit - basic (in dollars per share)	$ (6.11)	$ (12.71)
Common unit - diluted (in dollars per share)	$ (6.11)	$ (12.71)
Weighted-average limited partner units outstanding:
Common units - basic (in shares)	10,334	10,048
Common units - diluted (shares)	10,334	10,048
Gathering services and related fees
Revenues:
Total revenues	$ 248,223	$ 248,358
Natural gas, NGLs and condensate sales
Revenues:
Total revenues	179,254	86,225
Other revenues
Revenues:
Total revenues	$ 31,426	$ 35,011

INTANGIBLE ASSETS

12 Months Ended

Dec. 31, 2023

Goodwill and Intangible Assets Disclosure [Abstract]

INTANGIBLE ASSETS

6. INTANGIBLE ASSETS

Details regarding the Partnership’s intangible assets follow.


	December 31, 2023
	Gross carrying amount		Accumulated amortization		Net
	(In thousands)
Favorable gas gathering contracts	$	21,063	$	(15,747)	$	5,316
Contract intangibles	270,412		(247,024)		23,388
Rights-of-way	205,358		(66,906)		138,452
Indefinite-lived intangibles	8,436		—		8,436
Total intangible assets	$	505,269	$	(329,677)	$	175,592


	December 31, 2022
	Gross carrying amount		Accumulated amortization		Net
	(In thousands)
Favorable gas gathering contracts	$	21,063	$	(14,809)	$	6,254
Contract intangibles	270,412		(228,143)		42,269
Rights-of-way	200,089		(58,330)		141,759
Indefinite-lived intangibles	8,436		—		8,436
Total intangible assets	$	500,000	$	(301,282)	$	198,718

The Partnership recognized amortization expense of its favorable gas gathering contracts in Other revenues as follows:


	Year ended December 31,
	2023		2022
	(In thousands)
Amortization expense – favorable gas gathering contracts	$	938	$	938

The Partnership recognized amortization expense of its contract and right of way intangibles in costs and expenses as follows:


	Year ended December 31,
	2023		2022
	(In thousands)
Amortization expense – contract intangibles	$	18,881	$	18,935
Amortization expense – rights-of-way	8,576		6,527

The Partnership’s estimated aggregate annual amortization expected to be recognized for each of the five succeeding fiscal years and thereafter, as of December 31, 2023, follows.


	(In thousands)
2024	$	18,076
2025	17,892
2026	14,867
2027	8,878
2028	8,711
Thereafter	98,732
	$	167,156

LEASES - Lease Expense (Details) - USD ($) $ in Thousands	12 Months Ended
LEASES - Lease Expense (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Leases [Abstract]
Lease expense	$ 5,898	$ 3,162

LEASES - Schedule of Right of Use Assets and Lease Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
ROU assets
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other noncurrent assets	Other noncurrent assets
Operating	$ 10,352	$ 11,633
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other noncurrent assets	Other noncurrent assets
Finance	$ 2,400	$ 1,389
Total	$ 12,752	$ 13,022
Lease liabilities, current
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	Other current liabilities	Other current liabilities
Operating	$ 3,341	$ 2,570
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other current liabilities	Other current liabilities
Finance	$ 870	$ 435
Total	$ 4,211	$ 3,005
Lease liabilities, noncurrent
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Other noncurrent liabilities	Other noncurrent liabilities
Operating	$ 7,360	$ 9,672
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other noncurrent liabilities	Other noncurrent liabilities
Finance	$ 1,197	$ 679
Total	$ 8,557	$ 10,351

PROPERTY, PLANT, AND EQUIPMENT (Tables)

12 Months Ended

Dec. 31, 2023

Property, Plant and Equipment [Abstract]

Schedule of Property, Plant, and Equipment, Net

Details on the Partnership’s property, plant and equipment follow.


	December 31, 2023		December 31, 2022
	(In thousands)
Gathering and processing systems and related equipment	$	2,335,980	$	2,262,330
Construction in progress	56,064		59,036
Land and line fill	11,534		11,756
Other	65,029		62,222
Total	2,468,607		2,395,344
Less accumulated depreciation	(770,022)		(676,590)
Property, plant and equipment, net	$	1,698,585	$	1,718,754

Schedule of Depreciation Expense and Capitalized Interest Costs

Depreciation expense and capitalized interest for the Partnership follow.


	Year ended December 31,
	2023		2022
	(In thousands)
Depreciation expense	$	95,307	$	93,457
Capitalized interest	1,284		838

EQUITY METHOD INVESTMENTS - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments	$ (3,500)	$ (8,444)
Distributions from equity method investees	$ 57,572	43,040
Double E
Schedule of Equity Method Investments [Line Items]
Percentage of ownership interest (as a percent)	70.00%
Payments to acquire equity method investments	$ (3,500)	$ (8,400)
Distributions from equity method investees	28,300
Distribution made to partnership from total distributions	$ 19,800
OGC \| Principal Owner
Schedule of Equity Method Investments [Line Items]
Percentage of ownership interest (as a percent)		37.20%
OCC \| Principal Owner
Schedule of Equity Method Investments [Line Items]
Percentage of ownership interest (as a percent)	38.20%	38.20%
Ohio Gathering \| Principal Owner
Schedule of Equity Method Investments [Line Items]
Percentage of ownership interest (as a percent)	36.50%

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES AND RECENTLY ISSUED ACCOUNTING STANDARDS APPLICABLE TO THE PARTNERSHIP - Narrative (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Summary of Significant Accounting Policies [Line Items]
Restricted cash	$ 2,601	$ 1,723
Original terms (in years)	25 years
Favorable gas gathering contracts \| Minimum
Summary of Significant Accounting Policies [Line Items]
Useful lives (In years)	10 years
Favorable gas gathering contracts \| Maximum
Summary of Significant Accounting Policies [Line Items]
Useful lives (In years)	20 years
Other Gas Gathering Contract \| Minimum
Summary of Significant Accounting Policies [Line Items]
Useful lives (In years)	3 years
Other Gas Gathering Contract \| Maximum
Summary of Significant Accounting Policies [Line Items]
Useful lives (In years)	25 years
Rights-of-way \| Minimum
Summary of Significant Accounting Policies [Line Items]
Useful lives (In years)	20 years
Rights-of-way \| Maximum
Summary of Significant Accounting Policies [Line Items]
Useful lives (In years)	30 years

REVENUE - Schedule of Disaggregated Revenue by Geographic Area and Major Products and Services Reportable Segments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Disaggregation of Revenue [Line Items]
Total revenues	$ 458,903	$ 369,594
Corporate and other
Disaggregation of Revenue [Line Items]
Total revenues	(37)	1,003
Gathering services and related fees
Disaggregation of Revenue [Line Items]
Total revenues	248,223	248,358
Gathering services and related fees \| Corporate and other
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Natural gas, NGLs and condensate sales
Disaggregation of Revenue [Line Items]
Total revenues	179,254	86,225
Natural gas, NGLs and condensate sales \| Corporate and other
Disaggregation of Revenue [Line Items]
Total revenues	0	21
Other revenues
Disaggregation of Revenue [Line Items]
Total revenues	31,426	35,011
Other revenues \| Corporate and other
Disaggregation of Revenue [Line Items]
Total revenues	(37)	982
Reportable Segments
Disaggregation of Revenue [Line Items]
Total revenues	458,940	368,591
Reportable Segments \| Northeast
Disaggregation of Revenue [Line Items]
Total revenues	63,805	54,392
Reportable Segments \| Rockies
Disaggregation of Revenue [Line Items]
Total revenues	255,031	143,603
Reportable Segments \| Permian
Disaggregation of Revenue [Line Items]
Total revenues	3,570	25,151
Reportable Segments \| Piceance
Disaggregation of Revenue [Line Items]
Total revenues	91,417	93,349
Reportable Segments \| Barnett
Disaggregation of Revenue [Line Items]
Total revenues	45,117	52,096
Reportable Segments \| Gathering services and related fees
Disaggregation of Revenue [Line Items]
Total revenues	248,223	248,358
Reportable Segments \| Gathering services and related fees \| Northeast
Disaggregation of Revenue [Line Items]
Total revenues	63,805	54,392
Reportable Segments \| Gathering services and related fees \| Rockies
Disaggregation of Revenue [Line Items]
Total revenues	65,869	67,838
Reportable Segments \| Gathering services and related fees \| Permian
Disaggregation of Revenue [Line Items]
Total revenues	0	3,668
Reportable Segments \| Gathering services and related fees \| Piceance
Disaggregation of Revenue [Line Items]
Total revenues	81,041	80,630
Reportable Segments \| Gathering services and related fees \| Barnett
Disaggregation of Revenue [Line Items]
Total revenues	37,508	41,830
Reportable Segments \| Natural gas, NGLs and condensate sales
Disaggregation of Revenue [Line Items]
Total revenues	179,254	86,204
Reportable Segments \| Natural gas, NGLs and condensate sales \| Northeast
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Reportable Segments \| Natural gas, NGLs and condensate sales \| Rockies
Disaggregation of Revenue [Line Items]
Total revenues	173,688	59,208
Reportable Segments \| Natural gas, NGLs and condensate sales \| Permian
Disaggregation of Revenue [Line Items]
Total revenues	0	17,382
Reportable Segments \| Natural gas, NGLs and condensate sales \| Piceance
Disaggregation of Revenue [Line Items]
Total revenues	4,788	7,111
Reportable Segments \| Natural gas, NGLs and condensate sales \| Barnett
Disaggregation of Revenue [Line Items]
Total revenues	778	2,503
Reportable Segments \| Other revenues
Disaggregation of Revenue [Line Items]
Total revenues	31,463	34,029
Reportable Segments \| Other revenues \| Northeast
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Reportable Segments \| Other revenues \| Rockies
Disaggregation of Revenue [Line Items]
Total revenues	15,474	16,557
Reportable Segments \| Other revenues \| Permian
Disaggregation of Revenue [Line Items]
Total revenues	3,570	4,101
Reportable Segments \| Other revenues \| Piceance
Disaggregation of Revenue [Line Items]
Total revenues	5,588	5,608
Reportable Segments \| Other revenues \| Barnett
Disaggregation of Revenue [Line Items]
Total revenues	$ 6,831	$ 7,763

SEGMENT INFORMATION - Adjusted EBITDA by Reportable Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
Total of reportable segments' measures of profit	$ 291,766	$ 244,586
Northeast
Segment Reporting Information [Line Items]
Total of reportable segments' measures of profit	94,249	77,046
Rockies
Segment Reporting Information [Line Items]
Total of reportable segments' measures of profit	87,390	57,810
Permian
Segment Reporting Information [Line Items]
Total of reportable segments' measures of profit	24,207	18,051
Piceance
Segment Reporting Information [Line Items]
Total of reportable segments' measures of profit	59,749	60,055
Barnett
Segment Reporting Information [Line Items]
Total of reportable segments' measures of profit	$ 26,171	$ 31,624

INTANGIBLE ASSETS - Recognized Amortization Expense in Other Revenues and Cost and Expenses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Other Revenue \| Favorable gas gathering contracts
Finite-Lived Intangible Assets [Line Items]
Amortization expense	$ 938	$ 938
Costs And Expenses \| Contract intangibles
Finite-Lived Intangible Assets [Line Items]
Amortization expense	18,881	18,935
Costs And Expenses \| Rights-of-way
Finite-Lived Intangible Assets [Line Items]
Amortization expense	$ 8,576	$ 6,527

PARTNERS' CAPITAL AND MEZZANINE CAPITAL - Partners' Capital and Schedule of Units (Details) - shares	1 Months Ended	12 Months Ended
	Jan. 31, 2022	Dec. 31, 2023	Dec. 31, 2022
Common Units
Rollforwards of the number of partner units
Beginning balance (in shares)	7,169,834	10,182,763	7,169,834
2022 Preferred Exchange Offer, net of units withheld for taxes (in shares)	2,853,875		2,853,875
Common units issued for SMLP LTIP, net (in shares)		193,426	159,054
Ending balance (in shares)		10,376,189	10,182,763
Series A Preferred Units
Rollforwards of the number of partner units
Beginning balance (in shares)	143,447	65,508	143,447
2022 Preferred Exchange Offer (in shares)		0	(77,939)
Ending balance (in shares)		65,508	65,508

COMMITMENTS AND CONTINGENCIES (Tables)

12 Months Ended

Dec. 31, 2023

Commitments and Contingencies Disclosure [Abstract]

Schedule of Accrued Environmental Remediation

An update of the Partnership’s undiscounted accrued environmental remediation is as follows and is primarily related to the 2015 Blacktail Release and other environmental remediation activities, as described below.


	(In thousands)
Accrued environmental remediation, December 31, 2021	$	5,606
Payments made	(2,746)
Additional accruals	845
Accrued environmental remediation, December 31, 2022	$	3,705
Payments made	(641)
Changes in estimates	(127)
Accrued environmental remediation, December 31, 2023	$	2,937

EQUITY METHOD INVESTMENTS - Statements of Operations Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Nov. 30, 2023	Dec. 31, 2022	Nov. 30, 2022
Schedule of Equity Method Investments [Line Items]
Net loss	$ (38,947)		$ (123,461)
Equity Method Investment, Nonconsolidated Investee or Group of Investees
Schedule of Equity Method Investments [Line Items]
Total revenues	42,335		32,418
Total operating expenses	26,868		25,685
Net loss	$ 15,467		$ 6,733
Ohio Gathering
Schedule of Equity Method Investments [Line Items]
Total revenues		$ 138,707		$ 113,317
Total operating expenses		99,770		106,369
Net loss		38,937		6,948
OCC
Schedule of Equity Method Investments [Line Items]
Total revenues		15,603		13,340
Total operating expenses		12,285		12,786
Net loss		$ 3,318		$ 554

- Definition

The aggregate cost of goods produced and sold and services rendered during the reporting period.

+ References

+ Details

- Definition

The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

+ References

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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 14: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

- Definition

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ References

+ Details

EQUITY METHOD INVESTMENTS - Schedule of Equity Method Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Schedule of Equity Method Investments [Line Items]
Investment in equity method investees	$ 486,434	$ 506,677
Double E
Schedule of Equity Method Investments [Line Items]
Investment in equity method investees	276,221	281,640
Ohio Gathering
Schedule of Equity Method Investments [Line Items]
Investment in equity method investees	$ 210,213	$ 225,037

PROPERTY, PLANT, AND EQUIPMENT - Schedule of Depreciation Expense and Capitalized Interest (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 95,307	$ 93,457
Capitalized interest	$ 1,284	$ 838

EQUITY METHOD INVESTMENTS

12 Months Ended

Dec. 31, 2023

Equity Method Investments and Joint Ventures [Abstract]

EQUITY METHOD INVESTMENTS

7. EQUITY METHOD INVESTMENTS

The Partnership has equity method investments in Double E and Ohio Gathering, the balances of which are included in the Investment in equity method investees caption on the consolidated balance sheets. Details of the Partnership’s equity method investments follows.


	December 31, 2023		December 31, 2022
	(In thousands)
Double E (1)	$	276,221	$	281,640
Ohio Gathering	210,213		225,037
Total	$	486,434	$	506,677

(1) The Partnership’s investment balance in Double E includes capitalized interest costs.

Double E. The Partnership, through its wholly owned subsidiary Summit Permian Transmission, LLC, has a 70% ownership in Double E Pipeline, LLC (“Double E”). Double E owns a long-haul natural gas pipeline (the “Double E Pipeline”) that provides transportation service for residue natural gas from multiple receipt points in the Delaware Basin to various delivery points in and around the Waha hub in Texas. The Double E Pipeline commenced operations in November 2021 and during the years ended December 31, 2023 and 2022, the Partnership made cash investments of $3.5 million and $8.4 million, respectively, in Double E. During the year ended December 31, 2023, Double E made distributions to its investors totaling $28.3 million of which the Partnership received $19.8 million, of which all amounts were utilized for payment of interest and principal on the Permian Transmission Term Loan and distributions to the holders of the Subsidiary Series A Preferred Units.

Double E is deemed to be a variable interest entity as defined in GAAP. Summit Permian Transmission was not deemed to be the primary beneficiary of Double E due to the voting rights of Double E’s other owner regarding significant matters. The Partnership accounts for its ownership interest in Double E as an equity method investment because it has significant influence over Double E.

Summarized balance sheet information for Double E follows (amounts represent 100% of investee financial information).


	December 31, 2023		December 31, 2022
	(In thousands)
Current assets	$	11,410	$	5,121
Noncurrent assets	391,777		403,594
Total assets	$	403,187	$	408,715

Current liabilities	$	6,373	$	8,635
Noncurrent liabilities	13,727		9,137
Total liabilities	$	20,100	$	17,772

Summarized statements of operations information for Double E follows (amounts represent 100% of investee financial information).


	Year Ended December 31, 2023		Year Ended December 31, 2022
	(In thousands)
Total revenues	$	42,335	$	32,418
Total operating expenses	26,868		25,685
Net income	$	15,467	$	6,733

At December 31, 2023 and 2022, the Partnership’s carrying amount of its interest in Double E approximated its underlying investment.

Ohio Gathering. The Partnership has investments in OGC and OCC that are collectively referred to as Ohio Gathering. Ohio Gathering owns, operates and is currently developing midstream infrastructure consisting of a liquids-rich natural gas gathering system, a dry natural gas gathering system and a condensate stabilization facility in the Utica Shale in southeastern Ohio. Ohio Gathering provides gathering services pursuant to primarily long-term, fee-based gathering agreements, which include acreage dedications. The Partnership made its initial investment in Ohio Gathering in 2014 and owned approximately 36.5% of OGC and approximately 38.2% of OCC at December 31, 2023 and approximately 37.2% of OGC and approximately 38.2% of OCC at December 31, 2022.

Ohio Gathering is accounted for as an equity method investment because it has joint control with non-affiliated owners, which gives the Partnership significant influence.

A reconciliation of the difference between the carrying amount of the Partnership’s interest in Ohio Gathering and the Partnership’s underlying investment in Ohio Gathering, per Ohio Gathering’s books and records, is shown below.


	2023		2022
	(In thousands)
Investment in Ohio Gathering, December 31	$	210,213	$	225,037
December cash distributions	3,950		2,673

Basis difference (1)	190,600		199,263

Investment in Ohio Gathering (Books and records), November 30,	$	404,763	$	426,973

(1) Amount consists of differences created as a result of equity method impairment charges previously recognized which are being amortized over the remaining average life of the underlying assets.

Summarized balance sheet information for OGC and OCC follows (amounts represent 100% of investee financial information).


	November 30, 2023				November 30, 2022
	OGC		OCC		OGC		OCC
	(In thousands)
Current assets	$	42,716	$	5,885	$	36,062	$	5,195
Noncurrent assets	1,131,503		1,104		1,157,530		274
Total assets	$	1,174,219	$	6,989	$	1,193,592	$	5,469

Current liabilities	$	6,174	$	3,736	$	6,942	$	3,588
Noncurrent liabilities	14,088		1,149		13,380		3,096
Total liabilities	$	20,262	$	4,885	$	20,322	$	6,684

Summarized statements of operations information for OGC and OCC follows (amounts represent 100% of investee financial information).


	Twelve Months Ended November 30, 2023				Twelve Months Ended November 30, 2022
	OGC		OCC		OGC		OCC
	(In thousands)
Total revenues	$	138,707	$	15,603	$	113,317	$	13,340
Total operating expenses	99,770		12,285		106,369		12,786
Net income	38,937		3,318		6,948		554

SEGMENT INFORMATION (Tables)

12 Months Ended

Dec. 31, 2023

Segment Reporting [Abstract]

Schedule of Assets by Reportable Segment

Assets by reportable segment follow.


	December 31,
	2023		2022
	(in thousands)
Assets:
Northeast	$	573,663	$	591,091
Rockies	904,974		886,629
Permian	291,073		298,906
Piceance	431,687		475,719
Barnett	281,861		295,473
Total reportable segment assets	2,483,258		2,547,818
Corporate and Other	10,940		12,146
Total assets	$	2,494,198	$	2,559,964

Schedule of Segment Reporting Information

Revenues by reportable segment follow.


	Year ended December 31,
	2023		2022
	(In thousands)
Revenues:
Northeast	$	63,805	$	54,392
Rockies	255,031		143,603
Permian	3,570		25,151
Piceance	91,417		93,349
Barnett	45,117		52,096
Total reportable segments revenue	458,940		368,591
Corporate and Other	(37)		1,003

Total revenues	$	458,903	$	369,594

Depreciation and amortization, including the amortization expense associated with the Partnership’s favorable and unfavorable gas gathering contracts as reported in other revenues, by reportable segment follow.


	Year ended December 31,
	2023		2022
	(In thousands)
Depreciation and amortization:
Northeast	$	17,856	$	17,501
Rockies	36,148		30,532
Permian	—		2,736
Piceance	52,014		51,352
Barnett(1)	16,171		16,116
Total reportable segment depreciation and amortization	122,189		118,237
Corporate and Other	1,513		1,756
Total depreciation and amortization	$	123,702	$	119,993

______________________________________

(1)Includes the amortization expense associated with the Partnership’s favorable and unfavorable gas gathering contracts as reported in Other revenues.

Cash paid for capital expenditures by reportable segment follow.


	Year ended December 31,
	2023		2022
	(In thousands)
Cash paid for capital expenditures:
Northeast	$	4,695	$	8,743
Rockies	54,969		11,903
Permian	—		1,407
Piceance	4,544		6,116
Barnett	186		366
Total reportable segment capital expenditures	64,394		28,535
Corporate and Other	4,511		1,937
Total cash paid for capital expenditures	$	68,905	$	30,472

Schedule of Counterparties Accounting for More than 10% of Total Revenues

Counterparties accounting for a significant portion of total revenues were as follows:


	Year ended December 31,
	2023		2022
Percentage of total revenues:
Counterparty A - Piceance	10	%	13	%
Counterparty B - Rockies	13	%	*

________________________________________________________

* Less than 10% in the aggregate

Schedule of Reconciliation of Net Income to Adjusted EBITDA

Segment adjusted EBITDA by reportable segment follows.


	Year ended December 31,
	2023		2022
	(In thousands)
Reportable segment adjusted EBITDA
Northeast	$	94,249	$	77,046
Rockies	87,390		57,810
Permian	24,207		18,051
Piceance	59,749		60,055
Barnett	26,171		31,624
Total of reportable segments' measures of profit	$	291,766	$	244,586

A reconciliation of income or loss before income taxes and income or loss from equity method investees to total of reportable segments' measures of profit or loss follows.


	Year ended December 31,
	2023		2022
	(In thousands)
Reconciliation of loss before income taxes and income from equity method investees to total of reportable segments' measures of profit:
Loss before income taxes and income from equity method investees	$	(72,454)	$	(141,277)
Add:
Corporate and Other expense	30,758		29,118
Interest expense	140,784		102,459
Loss on early extinguishment of debt	10,934		—
Depreciation and amortization(1)	123,702		119,993
Proportional adjusted EBITDA for equity method investees	61,070		45,419
Adjustments related to capital reimbursement activity	(9,874)		(6,041)
Unit-based and noncash compensation	6,566		3,778
Gain on asset sales, net	(260)		(507)
Long-lived asset impairment	540		91,644
Total of reportable segments' measures of profit	$	291,766	$	244,586

______________________________________

(1)Includes the amortization expense associated with the Partnership’s favorable gas gathering contracts as reported in other revenues.

SUPPLEMENTAL CASH FLOW INFORMATION

12 Months Ended

Dec. 31, 2023

Supplemental Cash Flow Elements [Abstract]

SUPPLEMENTAL CASH FLOW INFORMATION

14. SUPPLEMENTAL CASH FLOW INFORMATION


	Year ended December 31,
	2023		2022
	(In thousands)
Supplemental cash flow information:
Cash interest paid	$	127,022	$	89,472
Cash paid for taxes	15		149

Noncash investing and financing activities:
Capital expenditures in trade accounts payable (period-end accruals)	$	11,612	$	6,724
2025 Senior Notes Exchange	180,030		—
Accretion of Subsidiary Series A Preferred Units	12,581		15,544
Right-of-use assets acquired in connection with Sterling DJ acquisition	—		9,865
2022 Preferred Exchange Offer	—		92,587

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Cash flows from operating activities:
Net loss	$ (38,947)	$ (123,461)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	123,702	119,993
Noncash lease expense	3,773	885
Amortization of debt issuance costs	12,685	9,326
Unit-based and noncash compensation	6,566	3,778
Income from equity method investees	(33,829)	(18,141)
Distributions from equity method investees	57,572	43,040
Gain on asset sales, net	(260)	(507)
Foreign currency gain	(102)	0
Loss on earn-out	599	0
Loss on sale of business	47	1,741
Loss on extinguishment of debt	10,934	0
Unrealized (gain) loss on interest rate swaps	3,318	(16,016)
Long-lived asset impairment	540	91,644
Changes in operating assets and liabilities:
Accounts receivable	(3,352)	284
Trade accounts payable	4,483	2,248
Accrued expenses	5,586	(2,780)
Deferred revenue	(6,467)	(6,082)
Ad valorem taxes payable	(1,702)	14
Accrued interest	1,943	4,618
Accrued environmental remediation, net	(768)	(1,901)
Other, net	(19,415)	(9,939)
Net cash provided by operating activities	126,906	98,744
Cash flows from investing activities:
Capital expenditures	(68,905)	(30,472)
Proceeds from asset sale	260	4,945
Investment in Double E equity method investee	(3,500)	(8,444)
Other, net	(2,611)	0
Net cash used in investing activities	(74,756)	(226,558)
Cash flows from financing activities:
Borrowings on 2026 Unsecured Notes	29,480	0
Repurchase of 2025 Senior Notes	(29,650)	0
Borrowings on 2026 Secured Notes	0	84,371
Repayments on Permian Transmission Term Loan	(10,507)	(4,647)
Borrowings on ABL Facility	70,000	293,000
Repayments on ABL Facility	(87,000)	(230,000)
Debt issuance costs	(2,968)	(14,409)
Payment for Debt Extinguishment or Debt Prepayment Cost	10,306	0
Distributions on Subsidiary Series A Preferred Units	(6,512)	(3,257)
Other, net	(1,573)	(3,285)
Net cash provided by financing activities	(49,036)	121,773
Net change in cash, cash equivalents and restricted cash	3,114	(6,041)
Cash, cash equivalents and restricted cash, beginning of period	13,531	19,572
Cash, cash equivalents and restricted cash, end of period	16,645	13,531
Lane G&P System
Cash flows from investing activities:
Proceeds from sale of business, net of cash sold in transaction	0	75,020
Bison Midstream, LLC
Cash flows from investing activities:
Proceeds from sale of business, net of cash sold in transaction	0	38,920
Outrigger DJ
Cash flows from investing activities:
Cash consideration paid for the acquisition, net of cash acquired	0	(166,631)
Sterling DJ
Cash flows from investing activities:
Cash consideration paid for the acquisition, net of cash acquired	$ 0	$ (139,896)

PROPERTY, PLANT, AND EQUIPMENT - Schedule of Property, Plant, and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 2,468,607	$ 2,395,344
Less accumulated depreciation	(770,022)	(676,590)
Property, plant and equipment, net	1,698,585	1,718,754
Gathering and processing systems and related equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	2,335,980	2,262,330
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	56,064	59,036
Land and line fill
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	11,534	11,756
Other
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 65,029	$ 62,222

EQUITY METHOD INVESTMENTS (Tables)

12 Months Ended

Dec. 31, 2023

Equity Method Investments and Joint Ventures [Abstract]

Schedule of Equity Method Investments

Details of the Partnership’s equity method investments follows.


	December 31, 2023		December 31, 2022
	(In thousands)
Double E (1)	$	276,221	$	281,640
Ohio Gathering	210,213		225,037
Total	$	486,434	$	506,677

(1) The Partnership’s investment balance in Double E includes capitalized interest costs.

Summarized balance sheet information for Double E follows (amounts represent 100% of investee financial information).


	December 31, 2023		December 31, 2022
	(In thousands)
Current assets	$	11,410	$	5,121
Noncurrent assets	391,777		403,594
Total assets	$	403,187	$	408,715

Current liabilities	$	6,373	$	8,635
Noncurrent liabilities	13,727		9,137
Total liabilities	$	20,100	$	17,772

Summarized statements of operations information for Double E follows (amounts represent 100% of investee financial information).


	Year Ended December 31, 2023		Year Ended December 31, 2022
	(In thousands)
Total revenues	$	42,335	$	32,418
Total operating expenses	26,868		25,685
Net income	$	15,467	$	6,733


	2023		2022
	(In thousands)
Investment in Ohio Gathering, December 31	$	210,213	$	225,037
December cash distributions	3,950		2,673

Basis difference (1)	190,600		199,263

Investment in Ohio Gathering (Books and records), November 30,	$	404,763	$	426,973

(1) Amount consists of differences created as a result of equity method impairment charges previously recognized which are being amortized over the remaining average life of the underlying assets.

Summarized balance sheet information for OGC and OCC follows (amounts represent 100% of investee financial information).


	November 30, 2023				November 30, 2022
	OGC		OCC		OGC		OCC
	(In thousands)
Current assets	$	42,716	$	5,885	$	36,062	$	5,195
Noncurrent assets	1,131,503		1,104		1,157,530		274
Total assets	$	1,174,219	$	6,989	$	1,193,592	$	5,469

Current liabilities	$	6,174	$	3,736	$	6,942	$	3,588
Noncurrent liabilities	14,088		1,149		13,380		3,096
Total liabilities	$	20,262	$	4,885	$	20,322	$	6,684

Summarized statements of operations information for OGC and OCC follows (amounts represent 100% of investee financial information).


	Twelve Months Ended November 30, 2023				Twelve Months Ended November 30, 2022
	OGC		OCC		OGC		OCC
	(In thousands)
Total revenues	$	138,707	$	15,603	$	113,317	$	13,340
Total operating expenses	99,770		12,285		106,369		12,786
Net income	38,937		3,318		6,948		554

PARTNERS' CAPITAL AND MEZZANINE CAPITAL - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions				1 Months Ended		3 Months Ended	12 Months Ended
	Dec. 15, 2023	Dec. 15, 2022	Jan. 21, 2020	Jan. 31, 2022	Nov. 30, 2017	Dec. 31, 2023	Dec. 31, 2023	Dec. 31, 2022
Partners Capital [Line Items]
Add: deemed capital contribution				$ 92.6
Maximum period following end of quarter to distribute all available cash							45 days
Subsidiary Series A Preferred Units
Partners Capital [Line Items]
Preferred units issued (in shares)						93,039,000	93,039,000
Preferred units issued during period (in shares)							1,600,000
Subsidiary Series A preferred unitholders, outstanding (in shares)						93,039,000	93,039,000
Common Units
Partners Capital [Line Items]
General partner units converted (in shares)				2,853,875				2,853,875
Series A Preferred Units
Partners Capital [Line Items]
Preferred units issued (in shares)				77,939	300,000
Interest in partnership per unit (in dollars per share)					$ 1,000
Distribution rate (as a percent)					9.50%		7.00%
Liquidation preference per unit (in dollars per share)					$ 1,000	$ 1,000	$ 1,000
Dividends payable						$ 33.0	$ 33.0
Redemption amount						$ 125.5	$ 125.5
Series A Preferred Units \| Paid-in-kind
Partners Capital [Line Items]
Distribution percentage of subsidiary unit (as a percent)			7.00%
Distribution percentage of liquidation preference rate of undrawn commitment units (as a percent)			1.00%
Series A Preferred Units \| London Interbank Offer Rate (LIBOR)
Partners Capital [Line Items]
Basis spread on variable rate (as a percent)	13.10%	7.43%
Series A Preferred Units \| Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Partners Capital [Line Items]
Basis spread on variable rate (as a percent)						7.69%

ORGANIZATION, BUSINESS OPERATIONS AND PRESENTATION AND CONSOLIDATION	12 Months Ended
	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
ORGANIZATION, BUSINESS OPERATIONS AND PRESENTATION AND CONSOLIDATION	1. ORGANIZATION, BUSINESS OPERATIONS AND PRESENTATION AND CONSOLIDATION Organization. Summit Midstream Partners, LP (including its subsidiaries, collectively “SMLP” or the “Partnership”) is a Delaware limited partnership that was formed in May 2012 and began operations in October 2012. SMLP is a value-oriented limited partnership focused on developing, owning and operating midstream energy infrastructure assets that are strategically located in unconventional resource basins, primarily shale formations, in the continental United States. The Partnership’s business activities are primarily conducted through various operating subsidiaries, each of which is owned or controlled by its wholly owned subsidiary holding company, Summit Holdings, a Delaware limited liability company. As of December 31, 2023, the Partnership indirectly owns its General Partner, and the General Partner is a wholly owned, indirect subsidiary of the Partnership. The General Partner has no assets or liabilities and holds the non-economic general partner interest in the Partnership. Business Operations. The Partnership provides natural gas gathering, compression, treating and processing services as well as crude oil and produced water gathering services pursuant to primarily long-term, fee-based agreements with its customers. In addition to these services, the Partnership also provides freshwater delivery services pursuant to short-term agreements with customers. The Partnership’s results are primarily driven by the volumes of natural gas that it gathers, compresses, treats and/or processes as well as by the volumes of crude oil and produced water that it gathers. Other than the Partnership’s investments in Double E and Ohio Gathering, all of its business activities are conducted through wholly owned operating subsidiaries. Presentation and Consolidation. The Partnership prepares its consolidated financial statements in accordance with GAAP as established by the FASB. The Partnership makes estimates and assumptions that affect the reported amounts of assets and liabilities at the balance sheet dates, including fair value measurements, the reported amounts of revenues and expenses and the disclosure of commitments and contingencies. Although management believes these estimates are reasonable, actual results could differ from its estimates. The consolidated financial statements include the assets, liabilities and results of operations of SMLP and its subsidiaries. All intercompany transactions among the consolidated entities have been eliminated in consolidation. Comprehensive income or loss is the same as net income or loss for all periods presented.

ACQUISTIONS AND DIVESTITURES

12 Months Ended

Dec. 31, 2023

Business Combination and Asset Acquisition [Abstract]

ACQUISTIONS AND DIVESTITURES

3. ACQUISTIONS AND DIVESTITURES

Acquisition of Outrigger DJ. On December 1, 2022, the Partnership completed the acquisition of 100% of the equity interests of Outrigger DJ Midstream LLC (“Outrigger DJ”) from Outrigger Energy II LLC for cash consideration of $165.0 million, subject to customary working capital adjustments. The acquisition of Outrigger DJ constituted a business combination and was accounted for using the acquisition method of accounting. For tax purposes, the acquisition was accounted for as an acquisition of assets. The acquisition significantly increased the Partnership’s gas processing capacity and footprint in the DJ Basin and diversified its customer base.

The following table sets forth the preliminary fair value of the assets acquired and liabilities assumed as of the acquisition date. There were no material changes made during 2023 to the provisional purchase accounting measurements initially recorded in December 2022 for the Outrigger DJ Acquisition. The purchase price allocation was complete as of the fourth quarter of 2023.


(in thousands)
Total consideration paid for Outrigger DJ	$	167,631
Recognized amounts of identifiable assets acquired and liabilities assumed:
Cash	1,000
Accounts receivable	7,529
Other current assets	190
Property, plant and equipment, net	144,514
Intangible assets	21,447
Trade accounts payable, accrued expenses and other	(7,049)
Net assets acquired and liabilities assumed	$	167,631

The assets acquired and liabilities assumed were recorded at their estimated fair values at the date of the acquisition. Acquired working capital amounts are expected to approximate fair value due to their short-term nature. The valuation of certain assets, including property, are based on appraisals. The fair value of acquired equipment is based on both available market data and cost and income approaches. These methods are considered Level 3 fair value estimates and include significant assumptions of future gathering and processing volumes, commodity prices, and operating and capital cost estimates, discounted using weighted average cost of capital for industry peers.

Intangible assets acquired consist of rights-of-way of $21.4 million with a weighted average amortization period of 30 years.

Acquisition of Sterling DJ. On December 1, 2022, the Partnership completed the acquisition of 100% of the equity interests in each of Sterling Energy Investments LLC, Grasslands Energy Marketing LLC and Centennial Water Pipelines LLC (collectively, “Sterling DJ”) from Sterling Investment Holdings LLC for cash consideration of $140.0 million, subject to customary working capital adjustments.. The acquisition of Sterling DJ constituted a business combination and was accounted for using the acquisition method of accounting. For tax purposes, the acquisition was accounted for as an acquisition of assets. The acquisition significantly increased the Partnership’s gas processing capacity and footprint in the DJ Basin and diversified its customer base.

The following table sets forth the preliminary fair value of the assets acquired and liabilities assumed as of the acquisition date. There were no material changes made during 2023 to the provisional purchase accounting measurements initially recorded in December 2022 for the Sterling DJ acquisition. The purchase price allocation was complete as of the fourth quarter of 2023.


(in thousands)
Total consideration paid for Sterling DJ	$	140,396
Recognized amounts of identifiable assets acquired and liabilities assumed:
Cash	500
Accounts receivable	16,224
Other current assets	4,557
Property, plant and equipment, net	108,720
Intangible assets	38,678
Other noncurrent assets	9,865
Trade accounts payable, accrued expenses and other	(38,148)
Net assets acquired	$	140,396

Intangible assets acquired consist of rights-of-way of $30.2 million with a weighted average amortization period of 30 years and indefinite-lived intangible assets of $8.4 million.

Divestiture of Lane G&P System. On June 30, 2022, the Partnership completed the sale of Summit Permian, which owns the Lane Gathering and Processing System (“Lane G&P System”), and Permian Finance to Longwood Gathering and Disposal Systems, LP (“Longwood”), a wholly owned subsidiary of Matador ͏Resources Company (“Matador”). In connection with the transaction, the Partnership released, to a subsidiary of Matador, and Matador agreed to assume, take or-pay firm capacity on the Double E Pipeline.

During 2022, the Partnership recognized an impairment of $84.5 million related to the disposition of the Lane G&P System based on total cash proceeds received of $75.0 million, including $2.0 million of cash sold in the transaction, net assets of $158.3 million, and other costs to sell of $1.2 million.

Divestiture of Bison Midstream. On September 19, 2022, the Partnership completed the sale of Bison Midstream, LLC (“Bison Midstream”), its gas gathering system in Burke and Mountrail Counties, North Dakota to a subsidiary of Steel Reef Infrastructure Corp. (“Steel Reef”), an integrated owner and operator of associated gas capture, gathering and processing assets in North Dakota and Saskatchewan.

During 2022, the Partnership recognized an impairment of $6.9 million related to the disposition of Bison Midstream based on total cash proceeds received of $38.9 million and net assets of $45.8 million. The cash proceeds were used to reduce amounts outstanding under the ABL Facility.

Pro Forma Information (Unaudited). The following table summarizes the unaudited pro forma condensed financial information of SMLP as if the acquisitions of Outrigger DJ and Sterling DJ, along with the dispositions of Bison Midstream and the Lane G&P System, had occurred on January 1, 2021:


	Year Ended December 31, 2022
Revenues	$	543,024
Net loss	$	(36,945)

The unaudited pro forma information is for informational purposes only and is not necessarily indicative of the operating results that would have occurred had the transactions been completed at January 1, 2021, nor is it necessarily indicative of future operating results. The financial data was adjusted to give effect to pro forma events that are i) directly attributable to the transactions, ii) factually supportable, and iii) expected to have a continuing impact on the consolidated results of operations.

Significant adjustments to the pro forma information above include adjustments to interest expense and depreciation based on the purchase price allocated to property, plant, and equipment.

Pay vs Performance Disclosure - USD ($) $ in Thousands	12 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Pay vs Performance Disclosure
Net loss attributable to Summit Midstream Partners, LP	$ (51,528)	$ (140,605)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

INTANGIBLE ASSETS (Tables)

12 Months Ended

Dec. 31, 2023

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Intangible Assets and Liabilities Subject to Amortization

Details regarding the Partnership’s intangible assets follow.


	December 31, 2023
	Gross carrying amount		Accumulated amortization		Net
	(In thousands)
Favorable gas gathering contracts	$	21,063	$	(15,747)	$	5,316
Contract intangibles	270,412		(247,024)		23,388
Rights-of-way	205,358		(66,906)		138,452
Indefinite-lived intangibles	8,436		—		8,436
Total intangible assets	$	505,269	$	(329,677)	$	175,592


	December 31, 2022
	Gross carrying amount		Accumulated amortization		Net
	(In thousands)
Favorable gas gathering contracts	$	21,063	$	(14,809)	$	6,254
Contract intangibles	270,412		(228,143)		42,269
Rights-of-way	200,089		(58,330)		141,759
Indefinite-lived intangibles	8,436		—		8,436
Total intangible assets	$	500,000	$	(301,282)	$	198,718

Schedule of Recognized Amortization Expense in Other Revenues and Cost and Expenses

The Partnership recognized amortization expense of its favorable gas gathering contracts in Other revenues as follows:


	Year ended December 31,
	2023		2022
	(In thousands)
Amortization expense – favorable gas gathering contracts	$	938	$	938

The Partnership recognized amortization expense of its contract and right of way intangibles in costs and expenses as follows:


	Year ended December 31,
	2023		2022
	(In thousands)
Amortization expense – contract intangibles	$	18,881	$	18,935
Amortization expense – rights-of-way	8,576		6,527

Schedule of Estimated Aggregate Annual Amortization Expected to be Recognized

The Partnership’s estimated aggregate annual amortization expected to be recognized for each of the five succeeding fiscal years and thereafter, as of December 31, 2023, follows.


	(In thousands)
2024	$	18,076
2025	17,892
2026	14,867
2027	8,878
2028	8,711
Thereafter	98,732
	$	167,156

UNIT-BASED AND NONCASH COMPENSATION - Narrative (Details) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) director $ / shares shares	Dec. 31, 2022 $ / shares shares	Dec. 31, 2021 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average remaining vesting period (in years)	11 months 23 days
SMLP LTIP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Reserved for issuance (in shares)	1,000,000
Units remaining available (in shares)	500,000
Unrecognized unit-based compensation \| $	$ 5.9
SMLP LTIP \| Phantom Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested phantom units granted (in shares)	688,467	605,142	333,779
Units granted (in shares)	323,371	509,631
Granted (in dollars per unit) \| $ / shares	$ 17.29	$ 17.70
SMLP LTIP \| Phantom Share Units And Associated Distribution Equivalent Rights
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Units granted (in shares)	212,893
Vesting period (in years)	3 years
SMLP LTIP \| Phantom Share Units And Associated Distribution Equivalent Rights \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in dollars per unit) \| $ / shares	$ 16.00
SMLP LTIP \| Phantom Share Units And Associated Distribution Equivalent Rights \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)	3 years
SMLP LTIP \| Common units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common units issued (in shares)	38,100
Number of directors \| director	6
Grant date fair value (in dollars per share) \| $ / shares	$ 16.00
SMLP LTIP \| Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Units granted (in shares)	110,478
Grant date fair value \| $	$ 2.2

LEASES (Tables)

12 Months Ended

Dec. 31, 2023

Leases [Abstract]

Schedule of Right-Of-Use Assets and Lease Liabilities

ROU assets (included in the other noncurrent assets caption on the Partnership’s consolidated balance sheet) and lease liabilities (included in the Other current liabilities and Other noncurrent liabilities captions on the Partnership’s consolidated balance sheet) follow:


	December 31, 2023		December 31, 2022
	(In thousands)

ROU assets
Operating	$	10,352	$	11,633
Finance	2,400		1,389
	$	12,752	$	13,022
Lease liabilities, current
Operating	$	3,341	$	2,570
Finance	870		435
	$	4,211	$	3,005
Lease liabilities, noncurrent
Operating	$	7,360	$	9,672
Finance	1,197		679
	$	8,557	$	10,351

Schedule of Lease Cost and Other Information

Lease cost and Other information follow:


	Year ended December 31,
	2023		2022
	(In thousands)
Lease cost
Finance lease cost:
Amortization of ROU assets (included in depreciation and amortization)	$	686	$	673
Interest on lease liabilities (included in interest expense)	62		18
Operating lease cost (included in general and administrative expense)	1,999		1,815
	$	2,747	$	2,506


	Year ended December 31,
	2023			2022
	(In thousands)
Other information
Cash paid for amounts included in the measurement of lease liabilities
Operating cash outflows from operating leases	$	3,975		$	1,732
Operating cash outflows from finance leases	62			18
Financing cash outflows from finance leases	610			330
ROU assets obtained in exchange for new operating lease liabilities	3,516			9,865
ROU assets obtained in exchange for new finance lease liabilities	1,238			1,298
Weighted-average remaining lease term (years) - operating leases	3.6			4.7
Weighted-average remaining lease term (years) - finance leases	2.5			2.4
Weighted-average discount rate - operating leases	6		%	6		%
Weighted-average discount rate - finance leases	5		%	3		%

The Partnership recognizes total lease expense incurred or allocated to us in general and administrative expenses. Lease expense related to operating leases, including lease expense incurred on the Partnership’s behalf and allocated to us, was as follows:


	Year ended December 31,
	2023		2022
	(In thousands)
Lease expense	$	5,898	$	3,162

Schedule of Future Minimum Lease Payments Due and Future Minimum Rentals to be Received Under Noncancelable Leases and Subleases

Future minimum lease payments due under noncancelable leases at December 31, 2023, were as follows:


	December 31, 2023
	(In thousands)
	Operating		Finance
2024	$	4,067	$	870
2025	3,573		736
2026	2,468		374
2027	2,074		87
2028	61		—
2029	27		—
Thereafter	330		—
Total future minimum lease payments	$	12,600	$	2,067

DEBT

12 Months Ended

Dec. 31, 2023

Debt Disclosure [Abstract]

DEBT

9. DEBT

Debt for the Partnership at December 31, 2023 and 2022 follows.


	December 31, 2023		December 31, 2022
	(In thousands)
ABL Facility: Summit Holdings’ asset based credit facility due May 1, 2026	$	313,000	$	330,000


Permian Transmission Term Loan: Permian Transmission’ variable rate senior secured term loan due January 2028	144,846		155,353
2026 Unsecured Notes: 12.00% senior unsecured notes due October 15, 2026	209,510		—

2025 Senior Notes: 5.75% senior unsecured notes due April 15, 2025	49,783		259,463

2026 Secured Notes: 8.50% senior second lien notes due October 15, 2026	785,000		785,000
Less: unamortized debt discount and debt issuance costs	(31,449)		(39,454)
Total debt, net of unamortized debt discount and debt issuance costs	1,470,690		1,490,362
Less: current portion of Permian Transmission Term Loan	(15,524)		(10,507)
Total long-term debt	$	1,455,166	$	1,479,855

The aggregate amount of Partnership’s debt maturing during each of the years after December 31, 2023 are as follows (in thousands):


2024	$	15,524
2025	66,363
2026	1,324,477
2027	17,769
2028	78,006
Thereafter	—
Total debt	$	1,502,139

ABL Facility. On November 2, 2021, the Partnership, the Partnership’s subsidiary, Summit Holdings, and the subsidiaries of

Summit Holdings party thereto entered into a first-lien, senior secured credit facility, consisting of a $400.0 million asset-based revolving credit facility (the “ABL Facility”), subject to a borrowing base comprised of a percentage of eligible accounts receivable of Summit Holdings and its subsidiaries that guarantee the ABL Facility (collectively, the “ABL Facility Subsidiary Guarantors”) and a percentage of eligible above-ground fixed assets including eligible compression units, processing plants, compression stations and related equipment of Summit Holdings and the ABL Facility Subsidiary Guarantors. As of December 31, 2023, the most recent borrowing base determination of eligible assets totaled $723.2 million, an amount greater than the $400.0 million of aggregate lending commitments.

As of December 31, 2023, the applicable margin under the adjusted term SOFR borrowings was 3.25%, the interest rate was 8.71% and the unused portion of the ABL Facility totaled $82.7 million after giving effect to the issuance of $4.3 million in outstanding but undrawn irrevocable standby letters of credit.

On November 16, 2023, the Partnership amended the ABL Facility to, among other things, permit the 2023 Exchange Transactions, address springing borrowing base reserves in relation to the outstanding principal amount of the 2025 Senior Notes and amend the Interest Coverage Ratio (as defined in the ABL Agreement) covenant to 1.75x through the end of 2024 and 1.90x thereafter.

Summit Holdings entered into that certain Loan and Security Agreement governing the ABL Facility (the “ABL Agreement”), dated as of November 2, 2021, by and among Summit Holdings, as borrower, the Partnership, the ABL Facility Subsidiary Guarantors, Bank of America, N.A., as agent, ING Capital LLC, Royal Bank of Canada and Regions Bank, as co-syndication agents, and Bank of America, N.A., ING Capital LLC, RBC Capital Markets and Regions Capital Markets, as joint lead arrangers and joint bookrunners.

The ABL Facility will mature on May 1, 2026; provided that if the outstanding amount of the 2025 Senior Notes (or any permitted refinancing indebtedness in respect thereof that has a final maturity, scheduled amortization or any other scheduled repayment, mandatory prepayment, mandatory redemption or sinking fund obligation prior to the date that is 120 days after the Termination Date (as defined in the ABL Agreement)) on such date equals or exceeds $50.0 million, then the ABL Facility will mature on December 13, 2024. As of December 31, 2023, the outstanding balance of the 2025 Senior Notes was $49.8 million.

The ABL Facility (together with certain Secured Bank Product Obligations (as defined in the ABL Agreement)) will be jointly and severally guaranteed, on a senior first-priority secured basis (subject to permitted liens), by the Partnership, Summit Holdings and each of the ABL Facility Subsidiary Guarantors.

The ABL Facility restricts, among other things, Summit Holdings’ and its Restricted Subsidiaries’ (as defined in the ABL Agreement) ability and the ability of certain of their subsidiaries to: (i) incur additional debt or issue preferred stock; (ii) make distributions or repurchase equity; (iii) make payments on or redeem junior lien, unsecured or subordinated indebtedness; (iv) create liens or other encumbrances; (v) make investments, loans or other guarantees; (vi) engage in transactions with affiliates; and (viii) make acquisitions or merge or consolidate with another entity. These covenants are subject both to a number of important exceptions and qualifications.

The ABL Facility requires that Summit Holdings not permit (i) the First Lien Net Leverage Ratio (as defined in the ABL Agreement) as of the last day of any fiscal quarter to be greater than 2.50:1.00, or (ii) the Interest Coverage Ratio (as defined in the ABL Agreement) as of the last day of any fiscal quarter to be less than 1.75:1.00 through the end of 2024 or less than 1.90:1.00 thereafter. As of December 31, 2023, the First Lien Net Leverage Ratio was 1.22:1.00 and the Interest Coverage Ratio was 1.93:1.00 and the Partnership was in compliance with the financial covenants of the ABL Facility.

The ABL Facility contains certain events of default customary for instruments of this type. In the case of an event of default arising from certain events of bankruptcy, insolvency or reorganization with respect to Summit Holdings, all outstanding Obligations (as defined in the ABL Agreement) will become due and payable immediately without further action or notice and all commitments under the ABL Facility will terminate.

Pursuant to the ABL Agreement, the Obligations (as defined in the ABL Agreement) are (or, subject to post-closing periods for certain types of collateral, will be) generally secured by a first priority lien on and security interest in (subject to permitted liens), subject to certain exclusions and limitations set forth in the ABL Agreement, (i) substantially all of the personal property of Summit Holdings and the ABL Facility Subsidiary Guarantors, (ii) all equity interests in Summit Holdings and certain other entities, all debt securities and certain rights related to the foregoing, in each case, owned by the Partnership, (iii) Closing Date Material Gathering Station Real Property and Closing Date Pipeline Material Gathering Station Real Property (each, as defined in the ABL Agreement) and certain other material real property interests (including improvements thereon) of Summit Holdings and the ABL Facility Subsidiary Guarantors as provided in the ABL Agreement and (iv) all proceeds of the foregoing collateral.

Intercreditor Agreement.

On November 2, 2021, in connection with the entry into the ABL Facility and issuance of the 2026 Secured Notes, Summit Holdings and the other guarantors party thereto entered into an Intercreditor Agreement (the “Intercreditor Agreement”) with Bank of America, N.A., as first lien representative and collateral agent for the initial first lien claimholders, Regions Bank, as second lien representative for the initial second lien claimholders and collateral agent for the initial second lien claimholders, establishing (i) a first-priority lien (subject to permitted liens) status for the liens on the collateral securing the ABL Facility and any additional first-lien indebtedness and (ii) a junior priority lien (subject to permitted liens) status for the liens on the collateral securing the 2026 Secured Notes and any additional second-lien indebtedness.

Permian Transmission Credit Facilities. On March 8, 2021 (the “Permian Closing Date”), the Partnership’s unrestricted subsidiary, Permian Transmission, entered into a Credit Agreement which allows for $175.0 million of senior secured credit facilities, including a $160.0 million Term Loan Facility and a $15.0 million Working Capital Facility. The Permian Transmission Credit Facilities can be used to finance Permian Transmission’s capital calls associated with its investment in Double E, debt service and other general corporate purposes. Unexpended proceeds from draws on the Permian Transmission Credit Facilities are classified as restricted cash on the accompanying unaudited condensed consolidated balance sheets.

On June 27, 2023, we amended the Permian Transmission Credit Facilities to, among other things, transition the LIBOR based interest rates under the Permian Transmission Credit Facilities to term SOFR.

As of December 31, 2023, the applicable margin under adjusted term SOFR borrowings was 2.475%, the interest rate was 7.79% and the unused portion of the Permian Transmission Credit Facilities totaled $4.5 million, subject to a commitment fee of 0.7% after giving effect to the issuance of $10.5 million in outstanding but undrawn irrevocable standby letters of credit. Summit Permian Transmission, LLC entered into interest rate hedges with notional amounts representing approximately 90% of the Permian Term Loan facility at a fixed SOFR rate of 1.23%. As of December 31, 2023, the Partnership was in compliance with the financial covenants of the Permian Transmission Credit Facilities.

Permian Transmission Term Loan. As described above, in January 2022, the Permian Term Loan Facility was converted into a Term Loan (the “Permian Transmission Term Loan”). The Permian Transmission Term Loan is due January 2028. As of December 31, 2023, the applicable margin under adjusted term SOFR borrowings was 2.475% and the interest rate was 7.79%. As of December 31, 2023, the Partnership was in compliance with the financial covenants governing the Permian Transmission Term Loan.

In accordance with the terms of the Permian Transmission Term Loan, Permian Transmission is required to make mandatory principal repayments. Below is a summary of the remaining mandatory principal repayments as of December 31, 2023:


(In thousands)	Total		2024		2025		2026		2027		2028
Amortizing principal repayments	$	144,846	$	15,524	$	16,580	$	16,967	$	17,769	$	78,006

2026 Secured Notes. In 2021, the Co-Issuers issued $700.0 million of 8.500% Senior Secured Second Lien Notes due 2026 (the “2026 Secured Notes”) to eligible purchasers pursuant to Rule 144A and Regulation S of the Securities Act, at a price of 98.5% of their face value. Additionally, in November 2022, in connection with the 2022 DJ Acquisitions, the Co-Issuers issued an additional $85.0 million of 2026 Secured Notes at a price of 99.26% of their face value. The 2026 Secured Notes will pay interest semi-annually on April 15 and October 15 of each year, commencing on April 15, 2022, and are jointly and severally guaranteed, on a senior second-priority secured basis (subject to permitted liens), by the Partnership and each restricted subsidiary of the Partnership (other than the Co-Issuers) that is an obligor under the ABL Agreement, or under the Co-Issuers’ 2025 Senior Notes on the issue date of the 2026 Secured Notes.

The 2026 Secured Notes will mature on October 15, 2026; provided that, if the outstanding amount of the 2025 Senior Notes (or any refinancing indebtedness in respect thereof that has a final maturity on or prior to the date that is 91 days after the Initial Maturity Date (as defined in the 2026 Secured Notes Indenture)) is greater than or equal to $50.0 million on January 14, 2025, which is 91 days prior to the scheduled maturity date of the 2025 Senior Notes, then the 2026 Secured Notes will mature on January 14, 2025.

The Partnership used the net proceeds from the offering of the 2026 Secured Notes, together with cash on hand and borrowings under the ABL Facility, to repay in full all of Summit Holdings’ obligations under the Revolving Credit Facility.

2026 Secured Notes Indenture.

The Co-Issuers issued the 2026 Secured Notes pursuant to an indenture (the “2026 Secured Notes Indenture”), dated as of November 2, 2021, by and among the Co-Issuers, the Partnership, any other Restricted Subsidiary (as defined in the 2026 Secured Notes Indenture) of the Partnership that provides a Notes Guarantee (as defined in the 2026 Secured Notes Indenture) and Regions Bank, as trustee (the “2026 Secured Notes Trustee”) and collateral agent, setting forth specific terms applicable to the 2026 Secured Notes.

At any time prior to October 15, 2023, the Co-Issuers could have on any one or more occasions redeemed up to 35% of the aggregate principal amount of the 2026 Secured Notes (including any additional notes) issued under the 2026 Secured Notes Indenture at a redemption price of 108.5% of the principal amount of the 2026 Secured Notes, plus accrued and unpaid interest, if any, to, but not including, the redemption date, in an amount not greater than the net cash proceeds of certain equity offerings by the Partnership, provided that: (i) at least 65% of the initial aggregate principal amount of the 2026 Secured Notes (including any additional notes) remains outstanding immediately after the occurrence of such redemption (excluding notes held by the Partnership and its subsidiaries); and (ii) the redemption occurs within 180 days of the date of the closing of each such equity offering by the Partnership. On and after October 15, 2023, the Co-Issuers may redeem all or part of the 2026 Secured Notes at redemption prices (expressed as percentages of principal amount) equal to: (a) 104.250% for the twelve-month period beginning October 15, 2023; (b) 102.125% for the twelve-month period beginning October 15, 2024; and (c) 100.000% for the twelve-month period beginning on October 15, 2025 and at any time thereafter, in each case plus accrued and unpaid interest, if any, to, but not including, the redemption date. In certain circumstances, the Co-Issuers will be required to offer to purchase the 2026 Secured Notes with excess proceeds from asset sales, excess cash flow and upon the occurrence of certain change of control events.

The 2026 Secured Notes Indenture restricts the Partnership’s and its Restricted Subsidiaries’ ability and the ability of certain of their subsidiaries to: (i) incur additional debt or issue preferred stock; (ii) make distributions, repurchase equity or redeem junior lien, unsecured or subordinated debt; (iii) make payments on junior lien, unsecured or subordinated indebtedness; (iv) create liens or other encumbrances; (v) make investments, loans or other guarantees; (vi) engage in transactions with affiliates; and (viii) make acquisitions or merge or consolidate with another entity. These covenants are subject both to a number of important exceptions and qualifications. At any time when the 2026 Secured Notes are rated investment grade by at least two of Moody’s Investors Service, Inc., Standard & Poor’s Ratings Services or Fitch Ratings, Inc., many of these covenants will terminate. As of December 31, 2023, the Partnership was in compliance with the financial covenants of the 2026 Secured Notes.

The 2026 Secured Notes Indenture contains certain events of default customary for instruments of this type.

In the case of an event of default arising from certain events of bankruptcy, insolvency or reorganization with respect to either Co-Issuer, the Partnership, and certain significant subsidiaries of the Partnership, all outstanding Notes will become due and payable immediately without further action or notice. If any other event of default occurs and is continuing, the 2026 Secured Notes Trustee or the holders of at least 25% in principal amount of the then outstanding Notes may declare all the 2026 Secured Notes to be due and payable immediately.

Collateral Agreement.

On November 2, 2021, the Co-Issuers, as pledgors and grantors, entered into, in connection with the 2026 Secured Notes Indenture, a Collateral Agreement (Second Lien), with the Partnership, as a pledgor, each subsidiary guarantor listed therein and Regions Bank, as collateral agent (the “Collateral Agreement”). Pursuant to the Collateral Agreement and the 2026 Secured Notes Indenture, the obligations under the 2026 Secured Notes Indenture are (or, subject to post-closing periods for certain types of collateral, will be) generally secured by a second priority lien on and security interest in (subject to permitted liens) the assets of the Partnership, the Co-Issuers and the subsidiary guarantors securing their obligations under the ABL Facility (as described above under “ABL Facility”).

Excess Cash Flow Offers to Purchase.

Starting in the first quarter of 2023 with respect to the fiscal year ended 2022, and continuing annually through the fiscal year 2025, the Partnership is required under the terms of the 2026 Secured Notes Indenture to, if it has Excess Cash Flow (as defined in the 2026 Secured Notes Indenture), and subject to its ability to make such an offer under the ABL Facility, offer to purchase an amount of the 2026 Secured Notes, at 100% of the principal amount plus accrued and unpaid interest, equal to 100% of the Excess Cash Flow generated in the prior year. Excess Cash Flow is generally defined as consolidated cash flow minus the sum of capital expenditures and cash payments in respect of permitted investments and permitted restricted payments.

Generally, if the Partnership does not offer to purchase designated annual amounts of its 2026 Secured Notes or reduce its first lien capacity under the 2026 Secured Notes Indenture per annum from 2023 through 2025, the interest rate on the 2026 Secured Notes is subject to certain rate escalations. Per the terms of the 2026 Secured Notes Indenture, the designated amounts are to offer to purchase $50.0 million aggregate principal amount of the 2026 Secured Notes by April 1, 2023, otherwise the interest rate shall automatically increase by 50 basis points per annum; $100.0 million aggregate principal amount of the 2026 Secured Notes by April 1, 2024, otherwise the interest rate shall automatically increase by 100 basis points per annum (minus any amount previously increased); and $200.0 million aggregate principal amount of the 2026 Secured Notes by April 1, 2025, otherwise the interest rate shall automatically increase by 200 basis points per annum (minus any amount previously increased). The Partnership does not anticipate making offers to purchase in the designated amount for the fiscal year ended 2023, and, as a result, the interest rate on the 2026 Secured Notes will increase an incremental 50 basis points to 9.50% effective April 1, 2024, resulting in an incremental increase in annual interest expense of approximately $3.9 million.

To the extent the Partnership makes an offer to purchase, and the offer is not fully accepted by the holders of the 2026 Secured Notes, the Partnership may use any remaining amount not accepted for any purpose not prohibited by the 2026 Secured Notes Indenture or the ABL Facility.

2026 Unsecured Notes. In November 2023, the Co-Issuers issued a total of $209.5 million aggregate principal amount of 2026 Unsecured Notes in exchange for $180.0 million aggregate principal amount of the 2025 Senior Notes and $29.5 million in cash. The cash raised was used to repurchase $29.7 million aggregate principal amount of the remaining 2025 Senior Notes that were not exchanged. The Partnership pays interest on the 2026 Unsecured Notes semi-annually in cash in arrears on April 15 and October 15 of each year. The 2026 Unsecured Notes are senior, unsecured obligations and rank equally in right of payment with all of the Partnership’s existing and future senior obligations. The 2026 Unsecured Notes are effectively subordinated in right of payment to all of the Partnership’s secured indebtedness, to the extent of the collateral securing such indebtedness.

The Co-Issuers have the right to redeem all or part of the 2026 Unsecured Notes at a redemption price of (a) on or before April 15, 2025, 101.000%, and (b) after April 15, 2025, 102.000%, plus accrued and unpaid interest, if any, to, but not including, the redemption date.

As December 31, 2023, the Partnership was in compliance with the financial covenants of the 2026 Unsecured Notes. The 2026 Unsecured Notes will mature on October 15, 2026.

2026 Unsecured Notes Indenture.

The Co-Issuers issued the 2026 Secured Notes pursuant to an indenture (the “2026 Unsecured Notes Indenture”), dated as of November 21, 2023, by and among the Co-Issuers, the guarantors party thereto and Regions Bank, as trustee (the “2026 Unsecured Notes Trustee”), setting forth specific terms applicable to the 2026 Unsecured Notes.

The indenture governing the 2026 Unsecured Notes restricts the Partnership’s and the Co-Issuers’ ability and the ability of certain of their subsidiaries to: (i) incur additional debt or issue preferred stock; (ii) make distributions, repurchase equity or redeem subordinated debt; (iii) make payments on subordinated indebtedness; (iv) create liens or other encumbrances; (v) make investments, loans or other guarantees; (vi) sell or otherwise dispose of a portion of their assets; (vii) engage in transactions with affiliates; and (viii) make acquisitions or merge or consolidate with another entity. These covenants are subject both to a number of important exceptions and qualifications. At any time when the 2026 Unsecured Notes are rated investment grade by Moody’s Investors Service, Inc. and Standard & Poor’s Ratings Services and no Default or Event of Default (each as defined in the indenture governing the 2026 Unsecured Notes) has occurred and is continuing, many of these covenants will terminate.

The indenture governing the 2026 Unsecured Notes provides that each of the following is an Event of Default: (i) default for 30 days in the payment when due of interest on the 2026 Unsecured Notes; (ii) default in payment when due of the principal of, or premium, if any, on the 2026 Unsecured Notes; (iii) failure by the Co-Issuers or the Partnership to comply with certain covenants relating to merger, consolidation, sale of assets, change of control or asset sales; (iv) failure by the Partnership for 180 days after notice to comply with certain covenants relating to the filing of annual, quarterly and current reports with the SEC; (v) failure by the Co-Issuers or the Partnership for 30 days after notice to comply with any of the other agreements in the indenture governing the 2026 Unsecured Notes; (vi) default under any mortgage, indenture or instrument under which there may be issued or by which there may be secured or evidenced any indebtedness for money borrowed by the Partnership or any of its restricted subsidiaries (or the payment of which is guaranteed by the Partnership or any of its restricted subsidiaries) if that default: (a) is caused by a failure to pay principal of, or interest or premium, if any, on such indebtedness prior to the expiration of the grace period provided in such indebtedness (a “Payment Default”); or (b) results in the acceleration of such indebtedness prior to its stated maturity, and, in each case, the principal amount of any such indebtedness, together with the principal amount of any other such indebtedness under which there has been a Payment Default or the maturity of which has been so accelerated, aggregates $75.0 million or more; (vii) failure by the Partnership or any of its restricted subsidiaries to pay final judgments aggregating in excess of $75.0 million, which judgments are not paid, discharged or stayed for a period of 60 days; (viii) except as permitted by the indenture governing the 2026 Unsecured Notes, any guarantee shall be held in any judicial proceeding to be unenforceable or invalid or shall cease for any reason to be in full force and effect or any Guarantor, or any person acting on behalf of any Guarantor, shall deny or disaffirm its obligations under its guarantee of the 2026 Unsecured Notes; and (ix) certain events of bankruptcy, insolvency or reorganization described in the indenture governing the 2026 Unsecured Notes with respect to the Co-Issuers, the Partnership or any of the Partnership’s restricted subsidiaries that is a significant subsidiary or any group of the Partnership’s restricted subsidiaries that, taken as a whole, would constitute a significant subsidiary of the Partnership.

In the case of an Event of Default arising from certain events of bankruptcy, insolvency or reorganization with respect to either Co-Issuer, the Partnership, any of the Partnership’s restricted subsidiaries that is a significant subsidiary or any group of the Partnership’s restricted subsidiaries that, taken as a whole, would constitute a significant subsidiary, all outstanding 2026 Unsecured Notes will become due and payable immediately without further action or notice. If any other Event of Default occurs and is continuing, the 2026 Unsecured Notes Trustee or the holders of at least 25% in principal amount of the then outstanding 2026 Unsecured Notes may declare all the 2026 Unsecured Notes to be due and payable immediately.

2025 Senior Notes. In February 2017, the Co-Issuers co-issued the 2025 Senior Notes. The Partnership pays interest on the 2025 Senior Notes semi-annually in cash in arrears on April 15 and October 15 of each year. The 2025 Senior Notes are senior, unsecured obligations and rank equally in right of payment with all of the Partnership’s existing and future senior obligations. The 2025 Senior Notes are effectively subordinated in right of payment to all of the Partnership’s secured indebtedness, to the extent of the collateral securing such indebtedness.

The Co-Issuers have the right to redeem all or part of the 2025 Senior Notes at a redemption price of 100.00%, plus accrued and unpaid interest, if any, to, but not including, the redemption date.

As discussed above, in November, 2023, the Partnership exchanged $180.0 million aggregate principal amount of the 2025 Senior Notes and repurchased $29.7 million aggregate principal amount of the remaining 2025 Senior Notes that were not exchanged. As of December 31, 2023, the outstanding balance of the 2025 Senior Notes was $49.8 million.

As of December 31, 2023, the Partnership was in compliance with the financial covenants of the 2025 Senior Notes. The 2025 Senior Notes will mature on April 15, 2025.

- Definition

The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (h)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(c))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 470
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//470/tableOfContent

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (g)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1C
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1C

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1C
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1C

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1C
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1C

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1E
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1E

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1I
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1I

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1I
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1I

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1I
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1I

+ Details

SEGMENT INFORMATION - Assets, Revenues, Depreciation and Amortization, and Capital Expenditures by Reportable Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
Total assets	$ 2,494,198	$ 2,559,964
Total revenues	458,903	369,594
Depreciation and amortization	123,702	119,993
Total cash paid for capital expenditures	68,905	30,472
Reportable Segments
Segment Reporting Information [Line Items]
Total assets	2,483,258	2,547,818
Total revenues	458,940	368,591
Depreciation and amortization	122,189	118,237
Total cash paid for capital expenditures	64,394	28,535
Reportable Segments \| Northeast
Segment Reporting Information [Line Items]
Total assets	573,663	591,091
Total revenues	63,805	54,392
Depreciation and amortization	17,856	17,501
Total cash paid for capital expenditures	4,695	8,743
Reportable Segments \| Rockies
Segment Reporting Information [Line Items]
Total assets	904,974	886,629
Total revenues	255,031	143,603
Depreciation and amortization	36,148	30,532
Total cash paid for capital expenditures	54,969	11,903
Reportable Segments \| Permian
Segment Reporting Information [Line Items]
Total assets	291,073	298,906
Total revenues	3,570	25,151
Depreciation and amortization	0	2,736
Total cash paid for capital expenditures	0	1,407
Reportable Segments \| Piceance
Segment Reporting Information [Line Items]
Total assets	431,687	475,719
Total revenues	91,417	93,349
Depreciation and amortization	52,014	51,352
Total cash paid for capital expenditures	4,544	6,116
Reportable Segments \| Barnett
Segment Reporting Information [Line Items]
Total assets	281,861	295,473
Total revenues	45,117	52,096
Depreciation and amortization	16,171	16,116
Total cash paid for capital expenditures	186	366
Corporate and Other
Segment Reporting Information [Line Items]
Total assets	10,940	12,146
Total revenues	(37)	1,003
Depreciation and amortization	1,513	1,756
Total cash paid for capital expenditures	$ 4,511	$ 1,937

UNIT-BASED AND NONCASH COMPENSATION (Tables)

12 Months Ended

Dec. 31, 2023

Share-Based Payment Arrangement [Abstract]

Schedule of Activity

The following table presents phantom unit activity for the periods presented:


	Units	Weighted-average grant date fair value
Nonvested phantom units, December 31, 2021	333,779	$	21.78
Phantom units granted	509,631	17.70
Phantom units vested	(229,551)	23.61
Phantom units forfeited	(8,717)	22.53
Nonvested phantom units, December 31, 2022	605,142	17.62
Phantom units granted	323,371	17.29
Phantom units vested	(236,154)	15.69
Phantom units forfeited	(3,892)	20.50
Nonvested phantom units, December 31, 2023	688,467	$	17.69

Schedule of Intrinsic Values

The intrinsic value of phantom units that vested during the years ended December 31, follows.


	Year ended December 31,
	2023		2022
	(In thousands)
Intrinsic value of vested LTIP awards	$	3,758	$	5,420

Schedule of Unit-Based Compensation Recognized in General and Administrative Expense

Unit-based compensation recognized in general and administrative expense related to awards under the SMLP LTIP follows.


	Year ended December 31,
	2023		2022
	(In thousands)
SMLP LTIP unit-based compensation	$	6,566	$	3,778

EQUITY METHOD INVESTMENTS - Balance Sheet Information (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Nov. 30, 2023	Dec. 31, 2022	Nov. 30, 2022
Schedule of Equity Method Investments [Line Items]
Current assets	$ 98,422		$ 97,542
TOTAL ASSETS	2,494,198		2,559,964
Current liabilities	134,012		117,889
Total liabilities	1,650,983		1,676,562
Equity Method Investment, Nonconsolidated Investee or Group of Investees
Schedule of Equity Method Investments [Line Items]
Current assets	11,410		5,121
Noncurrent assets	391,777		403,594
TOTAL ASSETS	403,187		408,715
Current liabilities	6,373		8,635
Noncurrent liabilities	13,727		9,137
Total liabilities	$ 20,100		$ 17,772
OGC
Schedule of Equity Method Investments [Line Items]
Current assets		$ 42,716		$ 36,062
Noncurrent assets		1,131,503		1,157,530
TOTAL ASSETS		1,174,219		1,193,592
Current liabilities		6,174		6,942
Noncurrent liabilities		14,088		13,380
Total liabilities		20,262		20,322
OCC
Schedule of Equity Method Investments [Line Items]
Current assets		5,885		5,195
Noncurrent assets		1,104		274
TOTAL ASSETS		6,989		5,469
Current liabilities		3,736		3,588
Noncurrent liabilities		1,149		3,096
Total liabilities		$ 4,885		$ 6,684

PARTNERS' CAPITAL AND MEZZANINE CAPITAL - Change in Subsidiary Series A Preferred Unit Balance (Details) - Series A Preferred Units - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Partners Capital [Line Items]
Issuance costs	$ 1,700	$ 2,200
Rollforwards of the number of partner units
Beginning Balance	118,584	106,325
PIK distributions		1,600
Redemption accretion, net of issuance cost amortization	12,581	15,544
Cash distribution	(6,513)	(4,885)
Ending Balance	124,652	$ 118,584
Distribution payable	$ 1,600

AUDIT INFORMATION	12 Months Ended
AUDIT INFORMATION	Dec. 31, 2023
Audit Information [Abstract]
Auditor Name	Deloitte & Touche LLP
Auditor Location	Houston, Texas
Auditor Firm ID	34

COMMITMENTS AND CONTINGENCIES

12 Months Ended

Dec. 31, 2023

Commitments and Contingencies Disclosure [Abstract]

COMMITMENTS AND CONTINGENCIES

10. COMMITMENTS AND CONTINGENCIES

Environmental Matters. Although the Partnership believes that it is in material compliance with applicable environmental regulations, the risk of environmental remediation costs and liabilities are inherent in pipeline ownership and operation. Furthermore, the Partnership can provide no assurances that significant environmental remediation costs and liabilities will not be incurred in the future. The Partnership is currently not aware of any material contingent liabilities that exist with respect to environmental matters, except as noted below.

As of December 31, 2023, the Partnership has recognized (i) a current liability for remediation effort expenditures expected to be incurred within the next 12 months and (ii) a noncurrent liability for estimated remediation expenditures expected to be incurred subsequent to December 31, 2024. Each of these amounts represent the Partnership’s best estimate for costs expected to be incurred. Neither of these amounts have been discounted to their present value.


	(In thousands)
Accrued environmental remediation, December 31, 2021	$	5,606
Payments made	(2,746)
Additional accruals	845
Accrued environmental remediation, December 31, 2022	$	3,705
Payments made	(641)
Changes in estimates	(127)
Accrued environmental remediation, December 31, 2023	$	2,937

In 2015, the Partnership learned of the rupture of a four-inch produced water gathering pipeline on the Meadowlark Midstream system near Williston, North Dakota (“2015 Blacktail Release”). On August 4, 2021, subsidiaries of the Partnership entered into the following agreements to resolve the U.S. federal and North Dakota state governments’ environmental claims with respect to the 2015 Blacktail Release: (i) a Consent Decree with the U.S. Department of Justice (“DOJ”), the U.S. Environmental Protection Agency (“EPA”), and the State of North Dakota (“Consent Decree”); (ii) a Plea Agreement with the United States (“Plea Agreement”); and (iii) a Consent Agreement with the North Dakota Industrial Commission (“Consent Agreement” together with the Consent Decree and Plea Agreement, the “Global Settlement”). As of December 31, 2023 and 2022, the accrued loss liability for the 2015 Blacktail Release was $21.7 million and $28.3 million, respectively, and are recorded within Other noncurrent liabilities and Accrued settlements payable within the consolidated balance sheets.

Key terms of the Global Settlement included (i) payment of penalties and fines totaling $36.3 million, consisting of $1.25 million in natural resource damages payable to federal and state governments, a $25.0 million payable to the federal government over five years, and a $10.0 million payable to state governments over, for the federal and state civil amounts six years, and, for the federal criminal amounts, five years, with interest applied to unpaid amounts accruing at, for the federal and state civil amounts, a fixed rate of 3.25%, and, for the federal criminal amounts, a variable rate set by statute, and of which $6.7 million is expected to be paid within the next twelve months; (ii) continuation of remediation efforts at the site of the 2015 Blacktail Release; (iii) other injunctive relief including but not limited to control room management, environmental management system audit, training, and reporting; (iv) guilty pleas by Defendant subsidiary for (a) one charge of negligent discharge of a harmful quantity of oil and (b) one charge of knowing failure to immediately report a discharge of oil; and (v) organizational probation for a minimum period of three years from sentencing on December 6, 2021, including payment in full of certain components of the fines and penalty amounts. The agreements comprising the Global Settlement were subject to the approval of the U.S. District Court for the District of North Dakota (the “U.S. District Court”). The U.S. District Court entered an order making the civil components of the Global Settlement effective on September 28, 2021 and accepted the sentencing in the Plea Agreement on December 6, 2021, completing approval of the Global Settlement.

Subsidiaries of the Partnership are also participating in two proceedings before the EPA as a result of the Plea Agreement becoming effective. Following the U.S. District Court’s entering judgment on Defendant subsidiary’s guilty plea to one count of negligent discharge of produced water in violation of the Clean Water Act, Defendant subsidiary was statutorily debarred by operation of law pursuant to 33 U.S.C. § 1368(a) to participate in federal awards performed at the “violating facility,” which EPA determined to be the Marmon subsystem of the produced water gathering system in North Dakota. The scope and effect of the debarment as defined did not materially affect the Partnership’s operations. Defendant has submitted a petition for reinstatement, which was denied by the EPA’s suspension and debarment office (“SDO”) on July 11, 2022. The SDO determined that the term of probation in the Plea Agreement was the appropriate period of time to demonstrate Defendant subsidiary’s change of corporate attitude, policies, practices, and procedures. The Partnership and certain subsidiaries have also received a show cause notice from the EPA requesting us to “show cause” why SDO should not issue a Notice of Proposed Debarment to the Defendant subsidiary and certain affiliates under 2 C.F.R. § 180.800(d), to which we have responded, and in which proceeding no further developments have occurred.

Legal Proceedings. The Partnership is involved in various litigation and administrative proceedings arising in the ordinary course of business. In the opinion of management, any liabilities, which include insured claims, would not individually or in the aggregate have a material adverse effect on the Partnership's financial position or results of operations.

UNIT-BASED AND NONCASH COMPENSATION - Schedule of Intrinsic Values (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
SMLP LTIP \| Phantom Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic value of vested LTIP awards	$ 3,758	$ 5,420

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

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-Publisher FASB
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

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-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

+ Details

DEBT - Narrative (Details)		1 Months Ended		12 Months Ended
DEBT - Narrative (Details)	Nov. 02, 2021 USD ($)	Nov. 30, 2023 USD ($)	Feb. 28, 2017	Dec. 31, 2023 USD ($) covenant	Dec. 31, 2022 USD ($)	Nov. 16, 2023	Nov. 30, 2022 USD ($)	Dec. 31, 2021 USD ($)	Mar. 08, 2021 USD ($)
Debt Instrument [Line Items]
Number of covenant \| covenant				2
Revolving credit facility \| Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)				3.25%
ABL Facility
Debt Instrument [Line Items]
Borrowing capacity	$ 400,000,000			$ 400,000,000
Borrowing base				$ 723,200,000
Interest rate (as a percent)				8.71%
Unused portion under the facility				$ 82,700,000
Secured notes				$ 4,300,000
Covenant, interest coverage ratio	1.75			1.93
Covenant, interest coverage ratio, thereafter	1.90
Mandatory redemption period (in days)				120 days
Maximum amount of debt outstanding for maturity to occur				$ 50,000,000
Covenant, first lien net leverage ratio	2.50			1.22
ABL Facility \| Revolving credit facility
Debt Instrument [Line Items]
Covenant, interest coverage ratio						1.75
Covenant, interest coverage ratio, thereafter						1.90
2025 Senior Notes
Debt Instrument [Line Items]
Stated interest rate (as a percent)				5.75%
2025 Senior Notes \| Senior Notes
Debt Instrument [Line Items]
Unsecured notes				$ 49,783,000	$ 259,463,000
Credit Agreement
Debt Instrument [Line Items]
Borrowing capacity									$ 175,000,000
Unused borrowing capacity amount				$ 4,500,000
Credit Agreement \| Summit Permian Transmission, LLC
Debt Instrument [Line Items]
Percentage of debt hedged by interest rate derivatives				90.00%
Credit Agreement \| Standby Letters of Credit
Debt Instrument [Line Items]
Unused borrowing capacity amount				$ 10,500,000
Credit Agreement \| Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)				2.475%
Interest rate (as a percent)				7.79%
Commitment fee (as a percent)				0.70%
Credit Agreement \| Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate \| Interest Rate Contract \| Summit Permian Transmission, LLC
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)				1.23%
Credit Agreement \| Term Loan Credit Facility
Debt Instrument [Line Items]
Borrowing capacity									160,000,000
Credit Agreement \| Working Capital Credit Facility
Debt Instrument [Line Items]
Borrowing capacity									$ 15,000,000
Permian Transmission Term Loan \| Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)				2.475%
2026 Notes
Debt Instrument [Line Items]
Debt instrument, amount							$ 85,000,000	$ 700,000,000
Stated interest rate (as a percent)								8.50%
Debt instrument issued as a percentage of face value (as a percent)							99.26%	98.50%
2025 Senior Notes
Debt Instrument [Line Items]
Mandatory redemption period (in days)	91 days
Maximum amount of debt outstanding for maturity to occur	$ 50,000,000
Debt instrument, amount		$ 180,000,000
Cash to certain purchasers		29,500,000
Debt instrument, repurchased face amount		29,700,000
2025 Senior Notes \| Redemption period three \| Summit Holdings and Finance Corporation
Debt Instrument [Line Items]
Redemption price, expressed as percentage of principal amount (as a percent)			100.00%
Secured Notes Indenture, 2026
Debt Instrument [Line Items]
Interest rate (as a percent)					9.50%
Redemption price, percentage of principal amount redeemed (as a percent)	35.00%
Redemption price, expressed as percentage of principal amount (as a percent)	108.50%
Covenant redemption, percent of initial principal amount remaining outstanding	65.00%
Ownership percentage of principal (as a percent)	25.00%
Repurchase amount of principal plus accrued interest (as a percent)	100.00%
Excess cash flow offer to purchase, period one	$ 50,000,000
Excess ash flow offer to purchase, basis point increase, period one	0.50%				0.50%
Excess cash flow offer to purchase, period two	$ 100,000,000
Excess cash flow offer to purchase, basis point increase, period two	1.00%
Excess cash flow offer to purchase, period three	$ 200,000,000
Excess cash flow offer to purchase, basis point increase, period three	2.00%
Interest expense					$ 3,900,000
Secured Notes Indenture, 2026 \| Redemption period one
Debt Instrument [Line Items]
Redemption price, expressed as percentage of principal amount (as a percent)	104.25%
Secured Notes Indenture, 2026 \| Redemption period two
Debt Instrument [Line Items]
Redemption price, expressed as percentage of principal amount (as a percent)	102.125%
Secured Notes Indenture, 2026 \| Redemption period three
Debt Instrument [Line Items]
Redemption price, expressed as percentage of principal amount (as a percent)	100.00%
2026 Unsecured Notes
Debt Instrument [Line Items]
Debt instrument, amount		$ 209,500,000
2026 Unsecured Notes \| Redemption period one \| Summit Holdings and Finance Corporation
Debt Instrument [Line Items]
Redemption price, expressed as percentage of principal amount (as a percent)		101.00%
2026 Unsecured Notes \| Redemption period two \| Summit Holdings and Finance Corporation
Debt Instrument [Line Items]
Redemption price, expressed as percentage of principal amount (as a percent)		102.00%
2026 Unsecured Notes Indenture
Debt Instrument [Line Items]
Debt default, compliance period (in days)		30 days
Payment default		$ 75,000,000
Restricted subsidiaries to pay final judgments		$ 75,000,000
Restricted subsidiaries, discharge period (in days)		60 days
Threshold percentage of principal amount outstanding (as a percent)		25.00%

SEGMENT INFORMATION - Concentration Risk (Details) - Sales Revenue, Net - Customer Concentration Risk	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Piceance
Segment Reporting Information [Line Items]
Concentration risk (as a percent)	10.00%	13.00%
Rockies
Segment Reporting Information [Line Items]
Concentration risk (as a percent)	13.00%

SEGMENT INFORMATION

12 Months Ended

Dec. 31, 2023

Segment Reporting [Abstract]

SEGMENT INFORMATION

17. SEGMENT INFORMATION

As of December 31, 2023, the Partnership’s current reportable segments are:

•Rockies – Includes the Partnership’s wholly owned midstream assets located in the Williston Basin and the DJ Basin.

•Permian – Includes the Partnership’s equity method investment in Double E.

•Northeast – Includes the Partnership’s wholly owned midstream assets located in the Utica and Marcellus shale plays and the equity method investment in Ohio Gathering that is focused on the Utica Shale.

•Piceance – Includes the Partnership’s wholly owned midstream assets located in the Piceance Basin.

•Barnett – Includes the Partnership’s wholly owned midstream assets located in the Barnett Shale.

Corporate and Other represents those results that: (i) are not specifically attributable to a reportable segment; (ii) are not individually reportable; or (iii) have not been allocated to a reportable segments for the purpose of evaluating their performance, including certain general and administrative expense items, certain natural gas and crude oil marketing services and transaction costs.

Assets by reportable segment follow.


	December 31,
	2023		2022
	(in thousands)
Assets:
Northeast	$	573,663	$	591,091
Rockies	904,974		886,629
Permian	291,073		298,906
Piceance	431,687		475,719
Barnett	281,861		295,473
Total reportable segment assets	2,483,258		2,547,818
Corporate and Other	10,940		12,146
Total assets	$	2,494,198	$	2,559,964

Revenues by reportable segment follow.


	Year ended December 31,
	2023		2022
	(In thousands)
Revenues:
Northeast	$	63,805	$	54,392
Rockies	255,031		143,603
Permian	3,570		25,151
Piceance	91,417		93,349
Barnett	45,117		52,096
Total reportable segments revenue	458,940		368,591
Corporate and Other	(37)		1,003

Total revenues	$	458,903	$	369,594

Counterparties accounting for a significant portion of total revenues were as follows:


	Year ended December 31,
	2023		2022
Percentage of total revenues:
Counterparty A - Piceance	10	%	13	%
Counterparty B - Rockies	13	%	*

________________________________________________________

* Less than 10% in the aggregate


	Year ended December 31,
	2023		2022
	(In thousands)
Depreciation and amortization:
Northeast	$	17,856	$	17,501
Rockies	36,148		30,532
Permian	—		2,736
Piceance	52,014		51,352
Barnett(1)	16,171		16,116
Total reportable segment depreciation and amortization	122,189		118,237
Corporate and Other	1,513		1,756
Total depreciation and amortization	$	123,702	$	119,993

______________________________________

(1)Includes the amortization expense associated with the Partnership’s favorable and unfavorable gas gathering contracts as reported in Other revenues.

Cash paid for capital expenditures by reportable segment follow.


	Year ended December 31,
	2023		2022
	(In thousands)
Cash paid for capital expenditures:
Northeast	$	4,695	$	8,743
Rockies	54,969		11,903
Permian	—		1,407
Piceance	4,544		6,116
Barnett	186		366
Total reportable segment capital expenditures	64,394		28,535
Corporate and Other	4,511		1,937
Total cash paid for capital expenditures	$	68,905	$	30,472

The Partnership assesses the performance of its reportable segments based on segment adjusted EBITDA. The Partnership defines segment adjusted EBITDA as total revenues less total costs and expenses; plus (i) other income excluding interest income, (ii) proportional adjusted EBITDA for equity method investees, (iii) depreciation and amortization, (iv) adjustments related to MVC shortfall payments, (v) adjustments related to capital reimbursement activity, (vi) unit-based and noncash compensation, (vii) impairments (vii) other noncash expenses or losses, less other noncash income or gains and (ix) restructuring expenses. Proportional adjusted EBITDA for the Partnership’s equity method investees is defined as the product of (i) total revenues less total expenses, excluding impairments and other noncash income or expense items, and amortization for deferred contract costs; and (ii) ownership interest in Ohio Gathering during the respective period.

For the purpose of evaluating segment performance, the Partnership excludes the effect of Corporate and Other revenues and expenses, such as certain general and administrative expenses (including compensation-related expenses and professional services fees), certain natural gas and crude oil marketing services, transaction costs, interest expense and income tax expense or benefit from segment adjusted EBITDA.

Segment adjusted EBITDA by reportable segment follows.


	Year ended December 31,
	2023		2022
	(In thousands)
Reportable segment adjusted EBITDA
Northeast	$	94,249	$	77,046
Rockies	87,390		57,810
Permian	24,207		18,051
Piceance	59,749		60,055
Barnett	26,171		31,624
Total of reportable segments' measures of profit	$	291,766	$	244,586

A reconciliation of income or loss before income taxes and income or loss from equity method investees to total of reportable segments' measures of profit or loss follows.


	Year ended December 31,
	2023		2022
	(In thousands)
Reconciliation of loss before income taxes and income from equity method investees to total of reportable segments' measures of profit:
Loss before income taxes and income from equity method investees	$	(72,454)	$	(141,277)
Add:
Corporate and Other expense	30,758		29,118
Interest expense	140,784		102,459
Loss on early extinguishment of debt	10,934		—
Depreciation and amortization(1)	123,702		119,993
Proportional adjusted EBITDA for equity method investees	61,070		45,419
Adjustments related to capital reimbursement activity	(9,874)		(6,041)
Unit-based and noncash compensation	6,566		3,778
Gain on asset sales, net	(260)		(507)
Long-lived asset impairment	540		91,644
Total of reportable segments' measures of profit	$	291,766	$	244,586

______________________________________

(1)Includes the amortization expense associated with the Partnership’s favorable gas gathering contracts as reported in other revenues.

Contributions in aid of construction are recognized over the remaining term of the respective contract. The Partnership includes adjustments related to capital reimbursement activity in its calculation of segment adjusted EBITDA to account for revenue recognized from contributions in aid of construction.

- Definition

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-22

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
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-Section 50
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-URI https://asc.fasb.org//1943274/2147482810/280-10-50-15

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
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-Name Accounting Standards Codification
-Section 50
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-URI https://asc.fasb.org//1943274/2147482810/280-10-50-31

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
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Reference 10: http://www.xbrl.org/2003/role/disclosureRef
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Reference 12: http://www.xbrl.org/2003/role/disclosureRef
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Reference 13: http://www.xbrl.org/2003/role/disclosureRef
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Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
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-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

+ Details

CONSOLIDATED STATEMENTS OF PARTNERS CAPITAL - USD ($) $ in Thousands	Total	Partners Capital	Partners Capital Series A Preferred Units
Beginning balance at Dec. 31, 2021	$ 904,363	$ 734,594	$ 169,769
Partners' Capital [Roll Forward]
Net income (loss)	(140,598)	(148,743)	8,145
Unit-based compensation	3,778	3,778	0
Tax withholdings and associated payments on vested SMLP LTIP awards	(1,198)	(1,198)	0
Tax withholdings on 2022 Preferred Exchange Offer	(2,652)	(2,652)	0
LTIP cash to equity conversion	1,125	1,125	0
Effect of 2022 Preferred Exchange Offer, inclusive of a $20.9 million deemed contribution to common unit holders	0	92,587	(92,587)
Ending balance at Dec. 31, 2022	764,818	679,491	85,327
Partners' Capital [Roll Forward]
Net income (loss)	(51,528)	(63,094)	11,566
Unit-based compensation	6,566	6,566	0
Tax withholdings and associated payments on vested SMLP LTIP awards	(1,293)	(1,293)	0
Ending balance at Dec. 31, 2023	$ 718,563	$ 621,670	$ 96,893

DEBT - Schedule of Maturities of Long-Term Debt (Details) $ in Thousands	Dec. 31, 2023 USD ($)
Debt Instrument [Line Items]
Total	$ 1,502,139
2024	15,524
2025	66,363
2026	1,324,477
2027	17,769
2028	78,006
Permian Transmission Term Loan
Debt Instrument [Line Items]
Total	144,846
2024	15,524
2025	16,580
2026	16,967
2027	17,769
2028	$ 78,006

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 835
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-Name Accounting Standards Codification
-Section 50
-Paragraph 1
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Reference 8: http://www.xbrl.org/2003/role/exampleRef
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
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-Paragraph 1B
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Reference 10: http://www.xbrl.org/2003/role/disclosureRef
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Reference 17: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

CONSOLIDATED BALANCE SHEETS (Parenthetical) - shares	Dec. 31, 2023	Dec. 31, 2022
Partners Capital
Common limited partner capital, issued (in shares)	10,376,189	10,182,763
Common limited partner capital, outstanding (in shares)	10,376,189	10,182,763
Subsidiary Series A Preferred Units
Subsidiary Series A preferred unitholders, issued (in shares)	93,039,000
Subsidiary Series A preferred unitholders, outstanding (in shares)	93,039,000
Series A Preferred Units
Subsidiary Series A preferred unitholders, issued (in shares)	65,508
Subsidiary Series A preferred unitholders, outstanding (in shares)	65,508

DEFERRED REVENUE (Tables)

12 Months Ended

Dec. 31, 2023

Revenue from Contract with Customer [Abstract]

Schedule of Rollforward Deferred Revenue

An update of current deferred revenue is as follows.


	(In thousands)
Current deferred revenue, January 1, 2023	$	9,054
Additions	10,970
Less: revenue recognized and other	(9,828)
Current deferred revenue, December 31, 2023	$	10,196

An update of noncurrent deferred revenue follows.


	(In thousands)
Noncurrent deferred revenue, January 1, 2023	$	37,694
Additions	2,951
Less: reclassification to current deferred revenue and other	(10,560)
Noncurrent deferred revenue, December 31, 2023	$	30,085

EARNINGS PER UNIT

12 Months Ended

Dec. 31, 2023

Earnings Per Share [Abstract]

EARNINGS PER UNIT

13. EARNINGS PER UNIT

The following table details the components of EPU.


	Year ended December 31,
	2023		2022
	(In thousands, except per-unit amounts)
Numerator for basic and diluted EPU:
Allocation of net loss among limited partner interests:
Net loss	$	(38,947)	$	(123,461)
Less: Net income attributable to Subsidiary Series A Preferred Units	(12,581)		(17,144)

Net loss attributable Summit Midstream Partners, LP	(51,528)		(140,605)

Less: Net income attributable to Series A Preferred Unit	(11,566)		(8,048)
Add: Deemed capital contribution	—		20,974
Net loss attributable to common limited partners	$	(63,094)	$	(127,679)

Denominator for basic and diluted EPU:
Weighted-average common units outstanding – basic	10,334		10,048
Effect of nonvested phantom units	—		—
Weighted-average common units outstanding – diluted	10,334		10,048

Net Loss per limited partner unit:
Common unit – basic	$	(6.11)	$	(12.71)
Common unit – diluted	$	(6.11)	$	(12.71)

Nonvested anti-dilutive phantom units excluded from the calculation of diluted EPU	245		177

COMMITMENTS AND CONTINGENCIES - Rollforward of Environmental Matters (Details) - Meadowlark Midstream Gathering System - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Accrual for Environmental Loss Contingencies [Roll Forward]
Accrued environmental remediation, beginning balance	$ 3,705	$ 5,606
Payments made	(641)	(2,746)
Additional accruals		845
Changes in estimates	(127)
Accrued environmental remediation, ending balance	$ 2,937	$ 3,705

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES AND RECENTLY ISSUED ACCOUNTING STANDARDS APPLICABLE TO THE PARTNERSHIP

12 Months Ended

Dec. 31, 2023

Accounting Policies [Abstract]

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES AND RECENTLY ISSUED ACCOUNTING STANDARDS APPLICABLE TO THE PARTNERSHIP

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES AND RECENTLY ISSUED ACCOUNTING STANDARDS APPLICABLE TO THE PARTNERSHIP

Cash, Cash Equivalents and Restricted Cash. The Partnership considers all highly liquid investments with an original maturity of three months or less to be cash equivalents. Cash that is held by a major bank and has restrictions on its availability to the Partnership is classified as restricted cash. The restricted cash balance of $2.6 million and $1.7 million at December 31, 2023 and 2022, respectively, is related to proceeds which are available to finance Permian Transmission’s debt service or other general corporate purposes of Permian Transmission. See Note 9 - Debt for additional information.

Accounts Receivable. Accounts receivable relate to gathering and other services provided to the Partnership’s customers and other counterparties. The Partnership evaluates the collectability of its accounts receivable and the need for an allowance for doubtful accounts based on customer-specific facts and circumstances. To the extent the collectability of a specific customer or counterparty receivable is doubtful, the Partnership recognizes an allowance for doubtful accounts. Uncollectible receivables are written off when a settlement is reached for an amount that is less than the outstanding historical balance or a receivable amount is deemed otherwise unrealizable.

Property, Plant and Equipment. The Partnership records property, plant and equipment at historical cost of construction or fair value of the assets at acquisition. The Partnership capitalizes expenditures that extend the useful life of an asset or enhance its productivity or efficiency from its original design over the expected remaining period of use. For maintenance and repairs that do not add capacity or extend the useful life of an asset, the Partnership recognizes expenditures as an expense as incurred. The Partnership capitalizes project costs incurred during construction, including interest on funds borrowed to finance the construction of facilities and pipelines, as construction in progress. Accrued capital expenditures are reflected in trade accounts payable.

The Partnership records depreciation on a straight-line basis over an asset’s estimated useful life and bases its estimates for useful life on various factors including age (in the case of acquired assets), manufacturing specifications, technological advances and historical data concerning useful lives of similar assets. Estimates of useful lives follow.


			Useful lives (In years)
Gathering and processing systems and related equipment			12-30
Other			3-15

Construction in progress is depreciated consistent with its applicable asset class once it is placed in service. Land and line fill are not depreciated.

The Partnership bases an asset’s carrying value on estimates, assumptions and judgments for useful life and salvage value. Upon sale, retirement or other disposal, the Partnership removes the carrying value of an asset and its accumulated depreciation from its balance sheet and recognizes the related gain or loss, if any.

Asset Retirement Obligations. The Partnership records a liability for asset retirement obligations only if and when a future asset retirement obligation with a determinable life is identified. For identified asset retirement obligations, the Partnership evaluates whether the expected retirement date and related costs of retirement can be estimated. The Partnership has concluded that its gathering and processing assets have an indeterminate life because they are owned and will operate for an indeterminate period when properly maintained. Because the Partnership does not have sufficient information to reasonably estimate the amount or timing of such obligations and does not have any current plan to discontinue use of any significant assets, the Partnership did not provide for any asset retirement obligations as of December 31, 2023 or 2022.

Amortizing Intangibles. The Partnership has certain acquired gas gathering contracts that had above-market pricing structures at the acquisition date and the Partnership amortizes these favorable contracts using a straight-line method over the contract’s estimated useful life. The Partnership defines useful life as the period over which the contract is expected to contribute to the Partnership’s future cash flows. These favorable contracts have original terms ranging from 10 years to 20 years and the Partnership recognizes the amortization expense associated with these contracts in Other revenues.

The Partnership amortizes all other gas gathering contracts, or contract intangibles, over the period of economic benefit based upon expected revenues over the life of the contract. The useful life of these contracts ranges from 3 years to 25 years. The Partnership recognizes the amortization expense associated with these contracts in Depreciation and amortization expense.

The Partnership also has rights-of-way associated with municipal easements and easements granted within existing rights-of-way. The Partnership amortizes these intangible assets over the shorter of the contractual term of the rights-of-way or the estimated useful life of the gathering system. The contractual terms of the rights-of-way range from 20 years to 30 years and the Partnership recognizes the amortization expense associated with these rights-of-way assets in Depreciation and amortization expense.

Equity Method Investments. The Partnership accounts for investments in which it exercises significant influence using the equity method so long as it (i) does not control the investee and (ii) is not the primary beneficiary. The Partnership reflects these investments in its consolidated balance sheets under the caption titled “investment in equity method investees.”

The Partnership recognizes an other-than-temporary impairment for losses in the value of equity method investees when evidence indicates that the carrying amount is no longer supportable. Evidence of a loss in value might include, but is not limited to, absence of an ability to recover the carrying amount of the investment or an inability of the equity method investee to sustain an earnings capacity that would justify the carrying amount of the investment. A current fair value of an investment that is less than its carrying amount may indicate a loss in value of the investment. The Partnership evaluates its equity method investments for impairment whenever a triggering event exists that would indicate a need to assess the investment for potential impairment.

Impairment of Long-Lived Assets. The Partnership tests assets for impairment when events or circumstances indicate the carrying value of a long-lived asset may not be recoverable. The carrying value of a long-lived asset is not recoverable if it exceeds the sum of the undiscounted cash flows expected to result from its use and eventual disposition. If the Partnership concludes that an asset’s carrying value will not be recovered through future cash flows, the Partnership recognizes an impairment loss on the long-lived asset equal to the amount by which the carrying value exceeds its fair value. The Partnership determines fair value using a combination of market-based and income-based approaches.

Environmental Matters. The Partnership is subject to various federal, state and local laws and regulations relating to the protection of the environment. Liabilities for loss contingencies, including environmental remediation costs, arising from claims, assessments, litigation, fines and penalties and other sources are charged to expense when it is probable that a liability has been incurred and the amount of the assessment and/or remediation can be reasonably estimated. The Partnership accrues

for losses associated with environmental remediation obligations when such losses are probable and reasonably estimable. Such accruals are adjusted as further information develops or circumstances change. Recoveries of environmental remediation costs from other parties or insurers are recorded as assets when their realization is assured beyond a reasonable doubt.

Commitments and Contingencies. When required, the Partnership records accruals for loss contingencies in accordance with FASB ASC 450, Contingencies. Such determinations are subject to interpretations of current facts and circumstances, forecasts of future events and estimates of the financial impacts of such events.

Mezzanine Capital. A noncontrolling interest is reported as a component of equity unless the noncontrolling interest is considered redeemable, in which case the noncontrolling interest is recorded between liabilities and equity (mezzanine or temporary equity) in the Partnership’s consolidated balance sheet.

Revenue. The Partnership provides gathering and/or processing services principally under contracts that contain one or more of the following arrangements described below:

•Fee-based arrangements. Under fee-based arrangements, the Partnership receives a fee or fees for one or more of the following services (i) natural gas gathering, treating, transporting, compressing and/or processing and (ii) crude oil and/or produced water gathering and (iii) fresh water delivery services.

•Percent-of-proceeds arrangements. Under percent-of-proceeds arrangements, the Partnership generally purchases natural gas from producers at the wellhead, or other receipt points, gathers the wellhead natural gas through its gathering system, treats and compresses the natural gas, processes the natural gas and/or sells the natural gas to a third party for processing. The Partnership then remits to its producers an agreed-upon percentage of the actual proceeds received from sales of the residue natural gas and NGLs. Certain of these arrangements may also result in returning all or a portion of the residue natural gas and/or the NGLs to the producer, in lieu of returning sales proceeds. The margins earned are directly related to the volume of natural gas that flows through the system and the price at which the Partnership is able to sell the residue natural gas and NGLs.

The majority of the Partnership’s contracts have a single performance obligation which is either to provide gathering services (an integrated service) or sell natural gas, NGLs and condensate, which are both satisfied when the related natural gas, crude oil and produced water are received and transferred to an agreed upon delivery point. The Partnership also has certain contracts with multiple performance obligations. They include an option for the customer to acquire additional services such as contracts containing MVCs. These performance obligations would also be satisfied when the related natural gas, crude oil and produced water are received and transferred to an agreed upon delivery point. In these instances, the Partnership allocates the contract’s transaction price to each performance obligation using its best estimate of the standalone selling price of each service in the contract.

Performance obligations for gathering services are generally satisfied over time. The Partnership utilizes either an output method (i.e., measure of progress) for guaranteed, stand-ready service contracts or an asset/system delivery time estimate for non-guaranteed, as-available service contracts.

Performance obligations for the sale of natural gas, NGLs and condensate are satisfied at a point in time. There are no significant judgments for these transactions because the customer obtains control based on an agreed upon delivery point.

Services are typically billed on a monthly basis and the Partnership does not offer extended payment terms. The Partnership does not have contracts with financing components.

For the contracts described above, the Partnership reflects its revenues in the financial statement captions described below.


Financial statement caption:						Revenue description:
Revenues:
Gathering services and related fees						•Revenue earned from fee-based gathering, compression, treating and processing services;
Natural gas, NGLs and condensate sales						•Revenue from the sale of physical natural gas purchased from customers percent-of- proceeds arrangements (Costs are presented within cost of natural gas and NGLs); •Revenue from sale of condensate and NGLs retained from gathering services (Costs are presented within operation and maintenance expense);
Other revenues						•Reimbursements to the Partnership for costs incurred by the Partnership on customer’s behalf (Recorded on a gross basis with corresponding costs included in operations and maintenance expense); •Revenue for freshwater deliveries; •Contract amortization; and •Revenue for management fees related to Double E.

Certain of the Partnership’s gathering and/or processing agreements provide for monthly MVCs. Under these MVCs, customers agree to ship and/or process a minimum volume of production on its gathering systems or to pay a minimum monetary amount over certain periods during the term of the MVC. A customer must make a shortfall payment to the Partnership at the end of the contracted measurement period if its actual throughput volumes are less than its contractual MVC for that period. Certain customers are entitled to utilize shortfall payments to offset gathering fees in one or more subsequent contracted measurement periods to the extent that such customers throughput volumes in a subsequent contracted measurement period exceed its MVC for that contracted measurement period. The amount of the shortfall payment is based on the difference between the actual throughput volume shipped and/or processed for the applicable period and the MVC for the applicable period, multiplied by the applicable gathering or processing fee.

Many of the Partnership’s gas gathering agreements contain provisions that can reduce or delay the cash flows that it expects to receive from MVCs to the extent that a customer's actual throughput volumes are above or below its MVC for the applicable contracted measurement period. These provisions include the following:

•To the extent that a customer's throughput volumes are less than its MVC for the applicable period and the customer makes a shortfall payment, it may be entitled to an offset in one or more subsequent periods to the extent that its throughput volumes in subsequent periods exceed its MVC for those periods. In such a situation, the Partnership would not receive gathering fees on throughput in excess of that customer's MVC (depending on the terms of the specific gas gathering agreement) to the extent that the customer had made a shortfall payment with respect to one or more preceding measurement periods (as applicable).

•To the extent that a customer's throughput volumes exceed its MVC in the applicable contracted measurement period, it may be entitled to apply the excess throughput against its aggregate MVC, thereby reducing the period for which its annual MVC applies. As a result of this mechanism, the weighted-average remaining period for which the Partnership’s MVCs apply will be less than the weighted-average of the originally stated MVC contractual terms.

•To the extent that certain of the Partnership’s customers' throughput volumes exceed its MVC for the applicable period, there is a crediting mechanism that allows the customer to build a bank of credits that it can utilize in the future to reduce shortfall payments owed in subsequent periods, subject to expiration if there is no shortfall in subsequent periods. The period over which this credit bank can be applied to future shortfall payments varies, depending on the particular gas gathering agreement.

The Partnership recognizes customer obligations under their MVCs as revenue and contract assets when (i) it considers it remote that the customer will utilize shortfall payments to offset gathering or processing fees in excess of its MVCs in subsequent periods; (ii) the customer incurs a shortfall in a contract with no banking mechanism or claw back provision; (iii) the customer’s banking mechanism has expired; or (iv) it is remote that the customer will use its unexercised right. In making

this determination, the Partnership considers both quantitative and qualitative facts and circumstances, including, but not limited to, contract terms, capacity of the associated pipeline or receipt point and/or expectations regarding future investment, drilling and production.

The majority of the Partnership’s revenue is derived from long-term, fee-based contracts with its customers, which include original terms of up to 25 years. The Partnership recognizes revenue earned from fee-based gathering, compression, treating and processing services in gathering services and related fees. The Partnership also earns revenue in the Rockies and Piceance reporting segments from the sale of physical natural gas purchased from its customers under certain percent-of-proceeds arrangements. Under ASC Topic 606, these gathering contracts are presented net within cost of natural gas and NGLs. The Partnership sells natural gas that it retains from certain customers in the Barnett reporting segment to offset the power expenses, included in operations and maintenance expense, of the electric-driven compression on the gathering system. The Partnership also sells condensate and NGLs retained from certain of its gathering services in the Piceance and Rockies reporting segments. Revenues from the sale of natural gas and condensate are recognized in Natural gas, NGLs and condensate sales; the associated expense is included in Operation and maintenance expense. Certain customers reimburse the Partnership for costs incurred on their behalf. The Partnership records costs incurred and reimbursed by its customers on a gross basis, with the revenue component recognized in Other revenues and the associated expense included in operations and maintenance expense.

The transaction price in the Partnership’s contracts is primarily based on the volume of natural gas, crude oil or produced water transferred by its gathering systems to the customer’s agreed upon delivery point multiplied by the contractual rate. For contracts that include MVCs, variable consideration up to the MVC will be included in the transaction price. For contracts that do not include MVCs, the Partnership does not estimate variable consideration because the performance obligations are completed and settled on a daily basis. For contracts containing noncash consideration such as fuel received in-kind, the Partnership measures the transaction price at the point of sale when the volume, mix and market price of the commodities are known.

The Partnership has contracts with MVCs that are variable and constrained. Contracts with longer than monthly MVCs are reviewed on a quarterly basis and adjustments to those estimates are made during each respective reporting period, if necessary.

The transaction price is allocated if the contract contains more than one performance obligation such as contracts that include MVCs. The transaction price allocated is based on the MVC for the applicable measurement period.

Unit-Based Compensation. For awards of unit-based compensation, the Partnership determines a grant date fair value and recognizes the related compensation expense in the statements of operations over the vesting period for each respective award.

Income Taxes. The Partnership is generally not subject to federal and state income taxes, except as noted below. However, its unitholders are individually responsible for paying federal and state income taxes on their share of its taxable income. Net income or loss for GAAP purposes may differ significantly from taxable income reportable to its unitholders as a result of differences between the tax basis and the GAAP basis of assets and liabilities and the taxable income allocation requirements of the Partnership’s governing documents. The aggregate difference in the basis of the Partnership’s net assets for financial and income tax purposes cannot be readily determined as the Partnership does not have access to the information about each partner’s tax attributes related to the Partnership.

In general, legal entities that are chartered, organized or conducting business in the state of Texas are subject to a franchise tax (the “Texas Margin Tax”). The Texas Margin Tax has the characteristics of an income tax because it is determined by applying a tax rate to a tax base that considers both revenues and expenses. The Partnership’s financial statements reflect provisions for these tax obligations.

Interest Rate Swaps. Interest rate swap agreements are reported as either assets or liabilities on the consolidated balance sheet at fair value. Interest rate swap agreements are not designated as cash-flow hedges, and accordingly, the changes in the fair value are recorded in earnings. The Partnership does not use interest rate swap agreements for speculative purposes.

Accounting standards recently implemented. ASU No. 2020-4 Reference Rate Reform (“ASU 2020-4”). ASU 2020-4 provides optional expedients and exceptions for applying GAAP to contracts, hedging relationships and other transactions affected by reference rate reform on financial reporting. Contract terms that are modified due to the replacement of a reference rate are not required to be remeasured or reassessed under relevant accounting standards. During the quarter ended June 30, 2023, the Partnership amended the terms of its Permian Transmission Credit Facility and Term Loan and interest rate swaps, which replaced its existing LIBOR based terms with SOFR rate terms. The amendments in ASU 2020-4 are effective as of March 12, 2020 through December 31, 2022. In December 2022, the FASB issued ASU 2022-06, which amended Topic 848 to defer the sunset date to apply the practical expedients until December 31, 2024. The impact of the change in reference rate did not have a material impact on the Partnership’s consolidated financial statements. See Note 9 - Debt, for additional information.

New accounting standards not yet implemented in this Annual Report. ASU No. 2020-06 Debt – Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging – Contracts in Entity’s Own Equity (Subtopic 815 – 40) (“ASU 2020-06”). ASU 2020-06 simplifies the accounting for certain financial instruments with characteristics of liabilities and equity, including convertible instruments and contracts on an entity’s own equity. The ASU is part of the FASB’s simplification initiative, which aims to reduce unnecessary complexity in GAAP. The ASU’s amendments are effective for fiscal years beginning after December 15, 2023, and interim periods within those fiscal years. The Partnership does not expect the provisions of ASU 2020-06 will have a material impact on its consolidated financial statements and disclosures.

ASU No. 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures (“ASU 2023-07”). ASU 2023-07 enhances disclosures on reportable segments and provides additional detailed information about significant segment expenses. The guidance in ASU 2023-07 is effective for fiscal years beginning after December 15, 2023 and interim periods within fiscal years beginning after December 15, 2024. The Partnership continues to assess the impact of the new guidance, but does not expect the provisions of ASU 2023-07 will have a material impact on its consolidated financial statements and disclosures.

UNIT-BASED AND NONCASH COMPENSATION - SMP Net Profits Interests (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
SMLP LTIP unit-based compensation	$ 6,566	$ 3,778
SMLP LTIP \| General and administrative expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
SMLP LTIP unit-based compensation		$ 3,778

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

+ Details

DEBT - Components of Long-Term Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Line of Credit Facility [Line Items]
Total	$ 1,502,139
Less: unamortized debt discount and debt issuance costs	(31,449)	$ (39,454)
Total debt, net of unamortized debt discount and debt issuance costs	1,470,690	1,490,362
Less: current portion of Permian Transmission Term Loan	(15,524)	(10,507)
Total long-term debt	1,455,166	1,479,855
Asset Backed Lending Facility \| Line of Credit
Line of Credit Facility [Line Items]
Secured notes	313,000	330,000
Permian Transmission Term Loan
Line of Credit Facility [Line Items]
Total	144,846
Permian Transmission Term Loan \| Line of Credit
Line of Credit Facility [Line Items]
Total	$ 144,846	155,353
2026 Unsecured Notes
Line of Credit Facility [Line Items]
Stated interest rate (as a percent)	12.00%
2026 Unsecured Notes \| Unsecured Debt
Line of Credit Facility [Line Items]
Unsecured notes	$ 209,510	0
2025 Senior Notes
Line of Credit Facility [Line Items]
Stated interest rate (as a percent)	5.75%
2025 Senior Notes \| Senior Notes
Line of Credit Facility [Line Items]
Unsecured notes	$ 49,783	259,463
2026 Secured Notes
Line of Credit Facility [Line Items]
Stated interest rate (as a percent)	8.50%
2026 Secured Notes \| Term Loan
Line of Credit Facility [Line Items]
Unsecured notes	$ 785,000	$ 785,000

FINANCIAL INSTRUMENTS

12 Months Ended

Dec. 31, 2023

Fair Value Disclosures [Abstract]

FINANCIAL INSTRUMENTS

11. FINANCIAL INSTRUMENTS

Concentrations of Credit Risk. Financial instruments that potentially subject the Partnership to concentrations of credit risk consist of cash and cash equivalents, restricted cash and accounts receivable. The Partnership maintains its cash and cash

equivalents and restricted cash in bank deposit accounts that frequently exceed federally insured limits. The Partnership has not experienced any losses in such accounts and does not believe it is exposed to any significant risk.

Accounts receivable primarily comprise amounts due for the gathering, compression, treating and processing services the Partnership provides to its customers and also the sale of natural gas liquids resulting from its processing services. This industry concentration has the potential to impact its overall exposure to credit risk, either positively or negatively, in that the Partnership’s customers may be similarly affected by changes in economic, industry or other conditions. The Partnership monitors the creditworthiness of its counterparties and can require letters of credit or other forms of credit assurance for receivables from counterparties that are judged to have substandard credit, unless the credit risk can otherwise be mitigated.

Fair Value. The carrying amount of cash and cash equivalents, restricted cash, accounts receivable and trade accounts payable reported on the consolidated balance sheet approximates fair value due to their short-term maturities.

A summary of the estimated fair value of the Partnership’s debt financial instruments follows.


	December 31, 2023				December 31, 2022
	Carrying Value (1)		Estimated fair value (Level 2)		Carrying Value (1)		Estimated fair value (Level 2)
	(in thousands)

2025 Senior Notes	$	49,783	$	48,414	$	259,463	$	221,733
2026 Secured Notes	$	785,000	$	778,131	$	785,000	$	750,983
2026 Unsecured Notes	$	209,510	$	203,225	$	—	$	—

(1) Excludes applicable unamortized debt issuance costs and debt discounts.

The carrying value on the balance sheets of the ABL Facility and Permian Transmission Term Loan represent their fair value due to its floating interest rate. The fair value for the 2026 Unsecured Notes, 2026 Secured Notes and 2025 Senior Notes is based on an average of nonbinding broker quotes as of December 31, 2023 and 2022. The use of different market assumptions or valuation methodologies may have a material effect on the estimated fair value of the Senior Notes.

Deferred earn-out. As a result of the acquisition of Sterling DJ, the Partnership assumed a deferred earn-out liability, which is remeasured each reporting period. As of December 31, 2023 and 2022, the estimated fair value of the deferred earn-out liability was $5.1 million and $5.2 million and was estimated using a discounted cash flow technique based on estimated future fresh water deliveries and appropriate discount rates, and the balances are recorded within other noncurrent liabilities on the consolidated balance sheets. Given the unobservable nature of the inputs, the fair value measurement of the deferred earn-out is deemed to use Level 3 inputs. The deferred earn-out sits within Centennial Water Pipelines LLC, one of the Partnership’s unrestricted subsidiaries.

Interest Rate Swaps. In connection with the Permian Transmission Term Loan, formerly the Permian Transmission Credit Facilities, the Partnership entered into amortizing interest rate swap agreements. As of December 31, 2023 and 2022, the outstanding notional amount of interest rate swaps was $130.4 million and $139.8 million, respectively. These interest rate swaps manage exposure to variability in expected cash flows attributable to interest rate risk. Interest rate swaps convert a portion of the Partnership’s variable rate debt to fixed rate debt. The Partnership chooses counterparties for its derivative instruments that it believes are creditworthy at the time the transactions are entered into, and the Partnership actively monitors the creditworthiness where applicable. However, there can be no assurance that a counterparty will be able to meet its obligations to the Partnership. The Partnership presents its derivative positions on a gross basis and does not net the asset and liability positions. During 2023, the Partnership amended its interest rate swap agreements to, among other things, replace its LIBOR based terms with a SOFR rate terms.

As of December 31, 2023 and 2022, the Partnership’s interest rate swap agreements had a fair value of $11.9 million and $15.2 million, respectively, and are recorded within other noncurrent assets within the consolidated balance sheets. The derivative instruments’ fair value are determined using level 2 inputs from the fair value hierarchy.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

LEASES

12 Months Ended

Dec. 31, 2023

Leases [Abstract]

LEASES

16. LEASES

Leases. The Partnership leases certain office space and equipment under operating leases. The Partnership leases office space for terms of between 3 and 10 years. Office space leases limit exposure to risks related to ownership, such as fluctuations in real estate prices. The Partnership leases equipment primarily to support its operations in response to the needs of its gathering systems for terms of between 3 and 4 years. The Partnership also leases vehicles under finance leases to support its operations in response to the needs of its gathering systems for a term of 3 years.

Some of the Partnership’s leases are subject to annual escalations relating to the Consumer Price Index (“CPI”). While lease liabilities are not remeasured as a result of changes to the CPI, changes to the CPI are treated as variable lease payments and recognized in the period in which the obligation for those payments was incurred.

Significant assumptions or judgments include the determination of whether a contract contains a lease and the discount rate used in the lease liabilities.

The rate implicit in the lease contracts are not readily determinable. In determining the discount rate used for lease liabilities, the Partnership analyzed certain factors in its incremental borrowing rate, including collateral assumptions and the term used. The Partnership’s incremental borrowing rate was 6.43% at December 31, 2023, which reflects the rate at which the Partnership could borrow a similar amount, for a similar term and with similar collateral as in the lease contracts at the commencement date.


	December 31, 2023		December 31, 2022
	(In thousands)

ROU assets
Operating	$	10,352	$	11,633
Finance	2,400		1,389
	$	12,752	$	13,022
Lease liabilities, current
Operating	$	3,341	$	2,570
Finance	870		435
	$	4,211	$	3,005
Lease liabilities, noncurrent
Operating	$	7,360	$	9,672
Finance	1,197		679
	$	8,557	$	10,351

Lease cost and Other information follow:


	Year ended December 31,
	2023		2022
	(In thousands)
Lease cost
Finance lease cost:
Amortization of ROU assets (included in depreciation and amortization)	$	686	$	673
Interest on lease liabilities (included in interest expense)	62		18
Operating lease cost (included in general and administrative expense)	1,999		1,815
	$	2,747	$	2,506


	Year ended December 31,
	2023			2022
	(In thousands)
Other information
Cash paid for amounts included in the measurement of lease liabilities
Operating cash outflows from operating leases	$	3,975		$	1,732
Operating cash outflows from finance leases	62			18
Financing cash outflows from finance leases	610			330
ROU assets obtained in exchange for new operating lease liabilities	3,516			9,865
ROU assets obtained in exchange for new finance lease liabilities	1,238			1,298
Weighted-average remaining lease term (years) - operating leases	3.6			4.7
Weighted-average remaining lease term (years) - finance leases	2.5			2.4
Weighted-average discount rate - operating leases	6		%	6		%
Weighted-average discount rate - finance leases	5		%	3		%


	Year ended December 31,
	2023		2022
	(In thousands)
Lease expense	$	5,898	$	3,162

Future minimum lease payments due under noncancelable leases at December 31, 2023, were as follows:


	December 31, 2023
	(In thousands)
	Operating		Finance
2024	$	4,067	$	870
2025	3,573		736
2026	2,468		374
2027	2,074		87
2028	61		—
2029	27		—
Thereafter	330		—
Total future minimum lease payments	$	12,600	$	2,067

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES AND RECENTLY ISSUED ACCOUNTING STANDARDS APPLICABLE TO THE PARTNERSHIP - Property, Plant and Equipment (Details)	Dec. 31, 2023
Gathering and processing systems and related equipment \| Minimum
Property, Plant and Equipment [Line Items]
Useful lives (In years)	12 years
Gathering and processing systems and related equipment \| Maximum
Property, Plant and Equipment [Line Items]
Useful lives (In years)	30 years
Other \| Minimum
Property, Plant and Equipment [Line Items]
Useful lives (In years)	3 years
Other \| Maximum
Property, Plant and Equipment [Line Items]
Useful lives (In years)	15 years

EQUITY METHOD INVESTMENTS - Rollforward of the Investment in Equity Method Investees (Details) - USD ($) $ in Thousands	11 Months Ended		12 Months Ended
	Nov. 30, 2023	Nov. 30, 2022	Dec. 31, 2023	Dec. 31, 2022
Equity Method Investment [Roll Forward]
Beginning balance	$ 506,677		$ 506,677
December cash distributions			57,572	$ 43,040
Ending balance			486,434	506,677
Ohio Gathering
Equity Method Investment [Roll Forward]
Beginning balance	225,037		225,037
Ending balance			210,213	225,037
Ohio Gathering \| Summit Midstream Partners, LLC
Equity Method Investment [Roll Forward]
Beginning balance	210,213	$ 225,037	$ 210,213	225,037
December cash distributions	3,950	2,673
Basis difference	190,600	199,263
Ending balance	$ 404,763	$ 426,973		$ 210,213

DEFERRED REVENUE

12 Months Ended

Dec. 31, 2023

Revenue from Contract with Customer [Abstract]

DEFERRED REVENUE

8. DEFERRED REVENUE

The balances in deferred revenue as of December 31, 2023 and 2022 are primarily related to contributions in aid of construction which will be recognized as revenue over the life of the contract. An update of current deferred revenue is as follows.


	(In thousands)
Current deferred revenue, January 1, 2023	$	9,054
Additions	10,970
Less: revenue recognized and other	(9,828)
Current deferred revenue, December 31, 2023	$	10,196

An update of noncurrent deferred revenue follows.


	(In thousands)
Noncurrent deferred revenue, January 1, 2023	$	37,694
Additions	2,951
Less: reclassification to current deferred revenue and other	(10,560)
Noncurrent deferred revenue, December 31, 2023	$	30,085

SUPPLEMENTAL CASH FLOW INFORMATION (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Supplemental cash flow information:
Cash interest paid	$ 127,022	$ 89,472
Cash paid for taxes	15	149
Noncash investing and financing activities:
Capital expenditures in trade accounts payable (period-end accruals)	11,612	6,724
Right-of-use assets acquired in connection with Sterling DJ acquisition	0	9,865
2022 Preferred Exchange Offer	0	92,587
2025 Senior Notes
Noncash investing and financing activities:
2025 Senior Notes Exchange	180,030	0
Series A Preferred Units
Noncash investing and financing activities:
Accretion of Subsidiary Series A Preferred Units	$ 12,581	$ 15,544

INTANGIBLE ASSETS - Estimated Aggregate Annual Amortization Expected to be Recognized (Details) $ in Thousands	Dec. 31, 2023 USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
2024	$ 18,076
2025	17,892
2026	14,867
2027	8,878
2028	8,711
Thereafter	98,732
Net	$ 167,156

COMMITMENTS AND CONTINGENCIES - Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) claim	Dec. 31, 2022 USD ($)
Loss Contingencies [Line Items]
Legal fines and other fees	$ 36,300
Claims settled \| claim	1
2015 Blacktail Release
Loss Contingencies [Line Items]
Loss contingency accrual	$ 21,700	$ 28,300
Penalties and fines, payment period	3 years
Unpaid penalties and fines, fixed rate (as a percent)	3.25%
Expected payment	$ 6,700
Claims settled \| claim	1
Pending claims \| claim	2
2015 Blacktail Release \| Natural Resource Damages To Federal and State Governments
Loss Contingencies [Line Items]
Legal fines and other fees	$ 1,250
Penalties and fines, payment period	5 years
2015 Blacktail Release \| Damages Payable To Federal Government over Five Years
Loss Contingencies [Line Items]
Legal fines and other fees	$ 25,000
2015 Blacktail Release \| Damages Payable To State Governments Over Six Years
Loss Contingencies [Line Items]
Legal fines and other fees	$ 10,000
Penalties and fines, payment period	6 years
2015 Blacktail Release \| Damages Payable To Federal Criminal Over Five Years
Loss Contingencies [Line Items]
Penalties and fines, payment period	5 years

UNIT-BASED AND NONCASH COMPENSATION - SMLP Long-Term Incentive Plan (Details) - SMLP LTIP - Phantom Units - $ / shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Units
Beginning balance (in shares)	605,142	333,779
Granted (in shares)	323,371	509,631
Vested (in shares)	(236,154)	(229,551)
Forfeited (in shares)	(3,892)	(8,717)
Ending balance (in shares)	688,467	605,142
Weighted-average grant date fair value
Beginning balance (in dollars per unit)	$ 17.62	$ 21.78
Granted (in dollars per unit)	17.29	17.70
Vested (in dollars per unit)	15.69	23.61
Forfeited (in dollars per unit)	20.50	22.53
Ending balance (in dollars per unit)	$ 17.69	$ 17.62

DEBT (Tables)

12 Months Ended

Dec. 31, 2023

Debt Disclosure [Abstract]

Schedule of Debt

Debt for the Partnership at December 31, 2023 and 2022 follows.


	December 31, 2023		December 31, 2022
	(In thousands)
ABL Facility: Summit Holdings’ asset based credit facility due May 1, 2026	$	313,000	$	330,000


Permian Transmission Term Loan: Permian Transmission’ variable rate senior secured term loan due January 2028	144,846		155,353
2026 Unsecured Notes: 12.00% senior unsecured notes due October 15, 2026	209,510		—

2025 Senior Notes: 5.75% senior unsecured notes due April 15, 2025	49,783		259,463

2026 Secured Notes: 8.50% senior second lien notes due October 15, 2026	785,000		785,000
Less: unamortized debt discount and debt issuance costs	(31,449)		(39,454)
Total debt, net of unamortized debt discount and debt issuance costs	1,470,690		1,490,362
Less: current portion of Permian Transmission Term Loan	(15,524)		(10,507)
Total long-term debt	$	1,455,166	$	1,479,855

Schedule of Maturities of Long-Term Debt

The aggregate amount of Partnership’s debt maturing during each of the years after December 31, 2023 are as follows (in thousands):


2024	$	15,524
2025	66,363
2026	1,324,477
2027	17,769
2028	78,006
Thereafter	—
Total debt	$	1,502,139

Below is a summary of the remaining mandatory principal repayments as of December 31, 2023:


(In thousands)	Total		2024		2025		2026		2027		2028
Amortizing principal repayments	$	144,846	$	15,524	$	16,580	$	16,967	$	17,769	$	78,006

- Definition

Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 470
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-Name Accounting Standards Codification
-Section 55
-Paragraph 69B
-Publisher FASB
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-URI https://asc.fasb.org//1943274/2147481568/470-20-55-69E

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
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-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 3
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-3

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+ Details

INTANGIBLE ASSETS - Intangible Assets and Liabilities Subject to Amortization (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Finite-Lived Intangible Assets [Line Items]
Accumulated amortization	$ (329,677)	$ (301,282)
Net	167,156
Indefinite-lived intangibles	8,436	8,436
Total intangibles, gross	505,269	500,000
Intangible Assets, Net (Excluding Goodwill), Total	175,592	198,718
Favorable gas gathering contracts
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	21,063	21,063
Accumulated amortization	(15,747)	(14,809)
Net	5,316	6,254
Contract intangibles
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	270,412	270,412
Accumulated amortization	(247,024)	(228,143)
Net	23,388	42,269
Rights-of-way
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	205,358	200,089
Accumulated amortization	(66,906)	(58,330)
Net	$ 138,452	$ 141,759

UNIT-BASED AND NONCASH COMPENSATION

12 Months Ended

Dec. 31, 2023

Share-Based Payment Arrangement [Abstract]

UNIT-BASED AND NONCASH COMPENSATION

15. UNIT-BASED AND NONCASH COMPENSATION

SMLP Long-Term Incentive Plan. The Partnership’s Long-Term Incentive Plan (“SMLP LTIP”) provides for equity awards to eligible officers, employees, consultants and directors of the Partnership, thereby linking the recipients' compensation directly to SMLP’s performance. The SMLP LTIP provides for the granting, from time to time, of unit-based awards, including common units, restricted units, phantom units, unit options, unit appreciation rights, distribution equivalent rights, profits interest units and other unit-based awards. Grants are made at the discretion of the Board of Directors or Compensation

Committee. Initially, a total of 1.0 million common units was reserved for issuance pursuant to and in accordance with the SMLP LTIP. On June 24, 2022 unitholders of the Partnership approved the Summit Midstream Partners, LP 2022 Long-Term Incentive Plan, which increased the number of common units available for issuance to the Partnership’s employees, consultants and directors. As of December 31, 2023, approximately 0.5 million common units remained available for future issuance under the SMLP LTIP, which includes the impact of 0.7 million granted but unvested phantom units.

Significant items for the year ended December 31, 2023:

•For the year ended December 31, 2023, the Partnership granted 212,893 phantom units and associated distribution equivalent rights to employees. These awards granted during the year ended December 31, 2023 had a fair values of $16.00 per common unit and vest ratably over a three-year period.

•For the year ended December 31, 2023, the Partnership granted 110,478 performance-based phantom units and associated distribution equivalent rights to certain members of management in connection with the Partnership’s annual incentive compensation award cycle. The grant date fair value of these awards total $2.2 million.

•For the year ended December 31, 2023, the Partnership issued 38,100 common units to the Partnership’s six independent directors in connection with their annual compensation plan. These awards had a grant date fair value of $16.00 per common unit and vested immediately.

The following table presents phantom unit activity for the periods presented:


	Units	Weighted-average grant date fair value
Nonvested phantom units, December 31, 2021	333,779	$	21.78
Phantom units granted	509,631	17.70
Phantom units vested	(229,551)	23.61
Phantom units forfeited	(8,717)	22.53
Nonvested phantom units, December 31, 2022	605,142	17.62
Phantom units granted	323,371	17.29
Phantom units vested	(236,154)	15.69
Phantom units forfeited	(3,892)	20.50
Nonvested phantom units, December 31, 2023	688,467	$	17.69

A phantom unit is a notional unit that entitles the grantee to receive a common unit upon the vesting of the phantom unit or on a deferred basis upon specified future dates or events or, in the discretion of the administrator, cash equal to the fair market value of a common unit. Distribution equivalent rights for each phantom unit provide for a lump sum cash amount equal to the accrued distributions from the grant date to be paid in cash upon the vesting date.

Phantom units granted to date generally vest ratably over a three-year period. Grant date fair value is determined based on the closing price of SMLP’s common units on the date of grant multiplied by the number of phantom units awarded to the grantee. Forfeitures are recorded as incurred. Holders of all phantom units granted to date are entitled to receive distribution equivalent rights for each phantom unit, providing for a lump sum cash amount equal to the accrued distributions from the grant date of the phantom units to be paid in cash upon the vesting date. Upon vesting, phantom unit awards may be settled, at the Partnership’s discretion, in cash and/or common units, but the current intention is to settle all phantom unit awards with common units.

The intrinsic value of phantom units that vested during the years ended December 31, follows.


	Year ended December 31,
	2023		2022
	(In thousands)
Intrinsic value of vested LTIP awards	$	3,758	$	5,420

As of December 31, 2023, the unrecognized unit-based compensation related to the SMLP LTIP was $5.9 million. Incremental unit-based compensation will be recorded over the remaining weighted-average vesting period of approximately 0.98 years.

Unit-based compensation recognized in general and administrative expense related to awards under the SMLP LTIP follows.


	Year ended December 31,
	2023		2022
	(In thousands)
SMLP LTIP unit-based compensation	$	6,566	$	3,778

SEGMENT INFORMATION - Reconciliation of Net Loss to Adjusted EBITDA (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting [Abstract]
Loss before income taxes and equity method investment income	$ (72,454)	$ (141,277)
Add:
Corporate and Other expense	30,758	29,118
Interest expense	140,784	102,459
Loss on early extinguishment of debt	10,934	0
Depreciation and amortization	123,702	119,993
Proportional adjusted EBITDA for equity method investees	61,070	45,419
Adjustments related to capital reimbursement activity	(9,874)	(6,041)
Unit-based and noncash compensation	6,566	3,778
Gain on asset sales, net	(260)	(507)
Long-lived asset impairment	540	91,644
Total of reportable segments' measures of profit	$ 291,766	$ 244,586

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
ASSETS
Cash and cash equivalents	$ 14,044	$ 11,808
Restricted cash	2,601	1,723
Accounts receivable	76,275	75,287
Other current assets	5,502	8,724
Total current assets	98,422	97,542
Property, plant and equipment, net	1,698,585	1,718,754
Intangible assets, net	175,592	198,718
Investment in equity method investees	486,434	506,677
Other noncurrent assets	35,165	38,273
TOTAL ASSETS	2,494,198	2,559,964
LIABILITIES AND CAPITAL
Trade accounts payable	22,714	14,052
Accrued expenses	32,377	20,601
Deferred revenue	10,196	9,054
Ad valorem taxes payable	8,543	10,245
Accrued compensation and employee benefits	6,815	16,319
Accrued interest	19,298	17,355
Accrued environmental remediation	1,483	1,365
Accrued settlement payable	6,667	6,667
Current portion of long-term debt	15,524	10,507
Other current liabilities	10,395	11,724
Total current liabilities	134,012	117,889
Long-term debt, net	1,455,166	1,479,855
Noncurrent deferred revenue	30,085	37,694
Noncurrent accrued environmental remediation	1,454	2,340
Other noncurrent liabilities	30,266	38,784
Total liabilities	1,650,983	1,676,562
Commitments and contingencies (Note 10)
Mezzanine Capital
Subsidiary Series A Preferred Units (93,039 units issued and outstanding at December 31, 2023 and December 31, 2022)	124,652	118,584
Partners Capital
Series A Preferred Units (65,508 units issued and outstanding at December 31, 2023 and December 31, 2022)	96,893	85,327
Common limited partner capital (10,376,189 and 10,182,763 units issued and outstanding at December 31, 2023 and December 31, 2022, respectively)	621,670	679,491
Total partners capital	718,563	764,818
TOTAL LIABILITIES AND CAPITAL	$ 2,494,198	$ 2,559,964

COVER PAGE - USD ($)	12 Months Ended
COVER PAGE - USD ($)	Dec. 31, 2023	Mar. 01, 2024	Jun. 30, 2023
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2023
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-35666
Entity Registrant Name	Summit Midstream Partners, LP
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	45-5200503
Entity Address, Address Line One	910 Louisiana Street
Entity Address, Address Line Two	Suite 4200
Entity Address, City or Town	Houston
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	77002
City Area Code	832
Local Phone Number	413-4770
Title of 12(b) Security	Common Units
Trading Symbol	SMLP
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Document Financial Statement Error Correction	false
Entity Shell Company	false
Entity Public Float			$ 168,613,071
Entity Common Stock, Shares Outstanding		10,415,675
Documents Incorporated by Reference	Portions of the registrant’s definitive proxy statement relating to its 2024 Annual Meeting of Limited Partners, which will be filed with the Securities and Exchange Commission within 120 days of December 31, 2023, are incorporated by reference into Part III of this Annual Report on Form 10-K where indicated.
Entity Central Index Key	0001549922
Amendment Flag	false
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY

FINANCIAL INSTRUMENTS (Tables)

12 Months Ended

Dec. 31, 2023

Fair Value Disclosures [Abstract]

Schedule of Estimated Fair Value of Debt Instruments

A summary of the estimated fair value of the Partnership’s debt financial instruments follows.


	December 31, 2023				December 31, 2022
	Carrying Value (1)		Estimated fair value (Level 2)		Carrying Value (1)		Estimated fair value (Level 2)
	(in thousands)

2025 Senior Notes	$	49,783	$	48,414	$	259,463	$	221,733
2026 Secured Notes	$	785,000	$	778,131	$	785,000	$	750,983
2026 Unsecured Notes	$	209,510	$	203,225	$	—	$	—

(1) Excludes applicable unamortized debt issuance costs and debt discounts.

LEASES - Schedule of Lease Cost and Other Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Lease cost
Amortization of ROU assets (included in depreciation and amortization)	$ 686	$ 673
Interest on lease liabilities (included in interest expense)	62	18
Operating lease cost (included in general and administrative expense)	1,999	1,815
Total lease cost	2,747	2,506
Other information
Operating cash outflows from operating leases	3,975	1,732
Operating cash outflows from finance leases	62	18
Financing cash outflows from finance leases	610	330
ROU assets obtained in exchange for new operating lease liabilities	3,516	9,865
ROU assets obtained in exchange for new finance lease liabilities	$ 1,238	$ 1,298
Weighted-average remaining lease term (years) - operating leases	3 years 7 months 6 days	4 years 8 months 12 days
Weighted-average remaining lease term (years) - finance leases	2 years 6 months	2 years 4 months 24 days
Weighted-average discount rate - operating leases (as a percent)	6.00%	6.00%
Weighted-average discount rate - finance leases (as a percent)	5.00%	3.00%

PROPERTY, PLANT, AND EQUIPMENT

12 Months Ended

Dec. 31, 2023

Property, Plant and Equipment [Abstract]

PROPERTY, PLANT, AND EQUIPMENT

5. PROPERTY, PLANT AND EQUIPMENT

Details on the Partnership’s property, plant and equipment follow.


	December 31, 2023		December 31, 2022
	(In thousands)
Gathering and processing systems and related equipment	$	2,335,980	$	2,262,330
Construction in progress	56,064		59,036
Land and line fill	11,534		11,756
Other	65,029		62,222
Total	2,468,607		2,395,344
Less accumulated depreciation	(770,022)		(676,590)
Property, plant and equipment, net	$	1,698,585	$	1,718,754

When the carrying amount of a long-lived asset is not recoverable, an impairment is recognized equal to the excess of the asset’s carrying value over its fair value, which is based on inputs that are not observable in the market, and thus represent Level 3 inputs under GAAP’s fair value hierarchy. The Partnership recognized $0.5 million and $91.6 million of impairments during the fiscal years ended December 31, 2023 and 2022, respectively. The Partnership cannot predict the likelihood of future impairments, if any.

Depreciation expense and capitalized interest for the Partnership follow.


	Year ended December 31,
	2023		2022
	(In thousands)
Depreciation expense	$	95,307	$	93,457
Capitalized interest	1,284		838

PROPERTY, PLANT, AND EQUIPMENT - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Abstract]
Long-lived asset impairment	$ 540	$ 91,644

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES AND RECENTLY ISSUED ACCOUNTING STANDARDS APPLICABLE TO THE PARTNERSHIP (Policies)

12 Months Ended

Dec. 31, 2023

Accounting Policies [Abstract]

Presentation and Consolidation

The Partnership prepares its consolidated financial statements in accordance with GAAP as established by the FASB. The Partnership makes estimates and assumptions that affect the reported amounts of assets and liabilities at the balance sheet dates, including fair value measurements, the reported amounts of revenues and expenses and the disclosure of commitments and contingencies. Although management believes these estimates are reasonable, actual results could differ from its estimates.

The consolidated financial statements include the assets, liabilities and results of operations of SMLP and its subsidiaries. All intercompany transactions among the consolidated entities have been eliminated in consolidation. Comprehensive income or loss is the same as net income or loss for all periods presented.

Cash, Cash Equivalents and Restricted Cash

The Partnership considers all highly liquid investments with an original maturity of three months or less to be cash equivalents. Cash that is held by a major bank and has restrictions on its availability to the Partnership is classified as restricted cash. The restricted cash balance of $2.6 million and $1.7 million at December 31, 2023 and 2022, respectively, is related to proceeds which are available to finance Permian Transmission’s debt service or other general corporate purposes of Permian Transmission. See Note 9 - Debt for additional information.

Accounts Receivable

Accounts receivable relate to gathering and other services provided to the Partnership’s customers and other counterparties. The Partnership evaluates the collectability of its accounts receivable and the need for an allowance for doubtful accounts based on customer-specific facts and circumstances. To the extent the collectability of a specific customer or counterparty receivable is doubtful, the Partnership recognizes an allowance for doubtful accounts. Uncollectible receivables are written off when a settlement is reached for an amount that is less than the outstanding historical balance or a receivable amount is deemed otherwise unrealizable.

Property, Plant and Equipment

The Partnership records property, plant and equipment at historical cost of construction or fair value of the assets at acquisition. The Partnership capitalizes expenditures that extend the useful life of an asset or enhance its productivity or efficiency from its original design over the expected remaining period of use. For maintenance and repairs that do not add capacity or extend the useful life of an asset, the Partnership recognizes expenditures as an expense as incurred. The Partnership capitalizes project costs incurred during construction, including interest on funds borrowed to finance the construction of facilities and pipelines, as construction in progress. Accrued capital expenditures are reflected in trade accounts payable.


			Useful lives (In years)
Gathering and processing systems and related equipment			12-30
Other			3-15

Construction in progress is depreciated consistent with its applicable asset class once it is placed in service. Land and line fill are not depreciated.

Asset Retirement Obligations

The Partnership records a liability for asset retirement obligations only if and when a future asset retirement obligation with a determinable life is identified. For identified asset retirement obligations, the Partnership evaluates whether the expected retirement date and related costs of retirement can be estimated. The Partnership has concluded that its gathering and processing assets have an indeterminate life because they are owned and will operate for an indeterminate period when properly maintained. Because the Partnership does not have sufficient information to reasonably estimate the amount or timing of such obligations and does not have any current plan to discontinue use of any significant assets, the Partnership did not provide for any asset retirement obligations as of December 31, 2023 or 2022.

Amortizing Intangibles

The Partnership has certain acquired gas gathering contracts that had above-market pricing structures at the acquisition date and the Partnership amortizes these favorable contracts using a straight-line method over the contract’s estimated useful life. The Partnership defines useful life as the period over which the contract is expected to contribute to the Partnership’s future cash flows. These favorable contracts have original terms ranging from 10 years to 20 years and the Partnership recognizes the amortization expense associated with these contracts in Other revenues.

Equity Method Investments

The Partnership accounts for investments in which it exercises significant influence using the equity method so long as it (i) does not control the investee and (ii) is not the primary beneficiary. The Partnership reflects these investments in its consolidated balance sheets under the caption titled “investment in equity method investees.”

Impairment of Long-Lived Assets

The Partnership tests assets for impairment when events or circumstances indicate the carrying value of a long-lived asset may not be recoverable. The carrying value of a long-lived asset is not recoverable if it exceeds the sum of the undiscounted cash flows expected to result from its use and eventual disposition. If the Partnership concludes that an asset’s carrying value will not be recovered through future cash flows, the Partnership recognizes an impairment loss on the long-lived asset equal to the amount by which the carrying value exceeds its fair value. The Partnership determines fair value using a combination of market-based and income-based approaches.

Environmental Matters

The Partnership is subject to various federal, state and local laws and regulations relating to the protection of the environment. Liabilities for loss contingencies, including environmental remediation costs, arising from claims, assessments, litigation, fines and penalties and other sources are charged to expense when it is probable that a liability has been incurred and the amount of the assessment and/or remediation can be reasonably estimated. The Partnership accrues

Commitments and Contingencies

When required, the Partnership records accruals for loss contingencies in accordance with FASB ASC 450, Contingencies. Such determinations are subject to interpretations of current facts and circumstances, forecasts of future events and estimates of the financial impacts of such events.

Mezzanine Capital

A noncontrolling interest is reported as a component of equity unless the noncontrolling interest is considered redeemable, in which case the noncontrolling interest is recorded between liabilities and equity (mezzanine or temporary equity) in the Partnership’s consolidated balance sheet.

Revenue Recognition

The Partnership provides gathering and/or processing services principally under contracts that contain one or more of the following arrangements described below:

Services are typically billed on a monthly basis and the Partnership does not offer extended payment terms. The Partnership does not have contracts with financing components.

For the contracts described above, the Partnership reflects its revenues in the financial statement captions described below.


Financial statement caption:						Revenue description:
Revenues:
Gathering services and related fees						•Revenue earned from fee-based gathering, compression, treating and processing services;
Natural gas, NGLs and condensate sales						•Revenue from the sale of physical natural gas purchased from customers percent-of- proceeds arrangements (Costs are presented within cost of natural gas and NGLs); •Revenue from sale of condensate and NGLs retained from gathering services (Costs are presented within operation and maintenance expense);
Other revenues						•Reimbursements to the Partnership for costs incurred by the Partnership on customer’s behalf (Recorded on a gross basis with corresponding costs included in operations and maintenance expense); •Revenue for freshwater deliveries; •Contract amortization; and •Revenue for management fees related to Double E.

Unit-Based Compensation

For awards of unit-based compensation, the Partnership determines a grant date fair value and recognizes the related compensation expense in the statements of operations over the vesting period for each respective award.

Income Taxes

The Partnership is generally not subject to federal and state income taxes, except as noted below. However, its unitholders are individually responsible for paying federal and state income taxes on their share of its taxable income. Net income or loss for GAAP purposes may differ significantly from taxable income reportable to its unitholders as a result of differences between the tax basis and the GAAP basis of assets and liabilities and the taxable income allocation requirements of the Partnership’s governing documents. The aggregate difference in the basis of the Partnership’s net assets for financial and income tax purposes cannot be readily determined as the Partnership does not have access to the information about each partner’s tax attributes related to the Partnership.

Interest Rate Swaps

Interest rate swap agreements are reported as either assets or liabilities on the consolidated balance sheet at fair value. Interest rate swap agreements are not designated as cash-flow hedges, and accordingly, the changes in the fair value are recorded in earnings. The Partnership does not use interest rate swap agreements for speculative purposes.

Accounting standards recently implemented. and New Accounting Standards Implemented in this Annual Report

LEASES - Narrative (Details)	12 Months Ended
LEASES - Narrative (Details)	Dec. 31, 2023
Loss Contingencies [Line Items]
Finance leases, term of contract (in years)	3 years
Revolving credit facility
Loss Contingencies [Line Items]
Percentage of operating lease incremental borrowing rate (as a percent)	6.43%
Minimum \| Office Space
Loss Contingencies [Line Items]
Operating leases, term of contract (in years)	3 years
Minimum \| Equipment
Loss Contingencies [Line Items]
Operating leases, term of contract (in years)	3 years
Maximum \| Office Space
Loss Contingencies [Line Items]
Operating leases, term of contract (in years)	10 years
Maximum \| Equipment
Loss Contingencies [Line Items]
Operating leases, term of contract (in years)	4 years

CONSOLIDATED STATEMENTS OF PARTNERS CAPITAL (Parenthetical) $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($)
Statement of Partners' Capital [Abstract]
Deemed contribution to common unit holders	$ 20.9

REVENUE

12 Months Ended

Dec. 31, 2023

Revenue from Contract with Customer [Abstract]

REVENUE

4. REVENUE

The following table presents estimated revenue expected to be recognized over the remaining contract period related to performance obligations that are unsatisfied and are comprised of estimated MVC shortfall payments.

The Partnership applies the practical expedient in paragraph 606-10-50-14 of Topic 606 for certain arrangements that are considered optional purchases (i.e., there is no enforceable obligation for the customer to make purchases) and those amounts are therefore excluded from the table.


	2024		2025		2026		2027		2028		Thereafter
	(in thousands)
Gathering services and related fees	$	65,472	$	45,594	$	29,292	$	7,685	$	5,137	$	—

Revenue by Category. In the following table, revenue is disaggregated by geographic area and major products and services. For more detailed information about reportable segments, see Note 17 -Segment Information.


	Year ended December 31, 2023
	Gathering services and related fees		Natural gas, NGLs and condensate sales		Other revenues		Total
	(in thousands)
Reportable Segments:
Northeast	$	63,805	$	—	$	—	$	63,805
Rockies	65,869		173,688		15,474		255,031
Permian	—		—		3,570		3,570
Piceance	81,041		4,788		5,588		91,417
Barnett	37,508		778		6,831		45,117
Total reportable segments	248,223		179,254		31,463		458,940
Corporate and other	—		—		(37)		(37)

Total	$	248,223	$	179,254	$	31,426	$	458,903


	Year ended December 31, 2022
	Gathering services and related fees		Natural gas, NGLs and condensate sales		Other revenues		Total
	(in thousands)
Reportable Segments:
Northeast	$	54,392	$	—	$	—	$	54,392
Rockies	67,838		59,208		16,557		143,603
Permian	3,668		17,382		4,101		25,151
Piceance	80,630		7,111		5,608		93,349
Barnett	41,830		2,503		7,763		52,096
Total reportable segments	248,358		86,204		34,029		368,591
Corporate and other	—		21		982		1,003
Total	$	248,358	$	86,225	$	35,011	$	369,594

- Definition

The entire disclosure of revenue from contract with customer to transfer good or service and to transfer nonfinancial asset. Includes, but is not limited to, disaggregation of revenue, credit loss recognized from contract with customer, judgment and change in judgment related to contract with customer, and asset recognized from cost incurred to obtain or fulfill contract with customer. Excludes insurance and lease contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-9

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-10

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 15
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-15

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-13

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Name Accounting Standards Codification
-Topic 606
-Publisher FASB
-URI https://asc.fasb.org//606/tableOfContent

+ Details

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Dec. 31, 2023
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

FINANCIAL INSTRUMENTS - Narrative (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Interest Rate Swap
CONCENTRATIONS OF RISK
Derivative instrument, notional amount	$ 130,400,000	$ 139,800,000
Fair value of interest rate swap	11,900,000	15,200,000
Fair Value, Inputs, Level 3
CONCENTRATIONS OF RISK
Deferred earn-out liability	$ 5,100,000	$ 5,200,000

DEFERRED REVENUE (Details) $ in Thousands	12 Months Ended
DEFERRED REVENUE (Details) $ in Thousands	Dec. 31, 2023 USD ($)
Change in Contract With Customer, Liability, Current [Roll Forward]
Beginning balance	$ 9,054
Additions	10,970
Less: revenue recognized and other	(9,828)
Ending balance	10,196
Change in Contract With Customer, Liability, Noncurrent [Roll Forward]
Beginning balance	37,694
Additions	2,951
Less: reclassification to current deferred revenue and other	(10,560)
Ending balance	$ 30,085

ACQUISTIONS AND DIVESTITURES - Narrative (Details) - USD ($) $ in Thousands		12 Months Ended
	Dec. 01, 2022	Dec. 31, 2023	Dec. 31, 2022
Lane G&P System
Business Acquisition [Line Items]
Proceeds from sale of business, net of cash sold in transaction		$ 0	$ 75,020
Bison Midstream, LLC
Business Acquisition [Line Items]
Proceeds from sale of business, net of cash sold in transaction		$ 0	38,920
Disposal, not discontinued operations \| Lane G&P System
Business Acquisition [Line Items]
Impairment on disposition			84,500
Proceeds from sale of business, net of cash sold in transaction			75,000
Cash sold, working capital and other miscellaneous adjustments			2,000
Net book value of assets and liabilities divested			158,300
Other costs to sell			1,200
Disposal, not discontinued operations \| Bison Midstream, LLC
Business Acquisition [Line Items]
Impairment on disposition			6,900
Proceeds from sale of business, net of cash sold in transaction			38,900
Net book value of assets and liabilities divested			$ 45,800
Outrigger DJ
Business Acquisition [Line Items]
Ownership interest (as a percent)	100.00%
Cash paid to acquire investment	$ 165,000
Intangible assets acquired	$ 21,447
Weighted average amortization period	30 years
Outrigger DJ \| Rights-Of-Way Intangibles
Business Acquisition [Line Items]
Intangible assets acquired	$ 21,400
Sterling DJ
Business Acquisition [Line Items]
Ownership interest (as a percent)	100.00%
Cash paid to acquire investment	$ 140,000
Intangible assets acquired	$ 38,678
Weighted average amortization period	30 years
Sterling DJ \| Rights-Of-Way Intangibles
Business Acquisition [Line Items]
Intangible assets acquired	$ 30,200
Sterling DJ \| Water Rights Intangibles
Business Acquisition [Line Items]
Intangible assets acquired	$ 8,400

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES AND RECENTLY ISSUED ACCOUNTING STANDARDS APPLICABLE TO THE PARTNERSHIP (Tables)

12 Months Ended

Dec. 31, 2023

Accounting Policies [Abstract]

Schedule of Useful lives of Property, Plant and Equipment

Estimates of useful lives follow.


			Useful lives (In years)
Gathering and processing systems and related equipment			12-30
Other			3-15

PARTNERS' CAPITAL AND MEZZANINE CAPITAL

12 Months Ended

Dec. 31, 2023

Equity [Abstract]

PARTNERS' CAPITAL AND MEZZANINE CAPITAL

12. PARTNERS' CAPITAL AND MEZZANINE CAPITAL

Common Units. An update on the number of common units is as follows for the period from December 31, 2021 to December 31, 2023.


			Common Units
December 31, 2021			7,169,834
2022 Preferred Exchange Offer, net of units withheld for taxes			2,853,875
Common units issued for SMLP LTIP, net			159,054



December 31, 2022			10,182,763

Common units issued for SMLP LTIP, net			193,426

December 31, 2023			10,376,189

Series A Preferred Units. In November 2017, the Partnership issued 300,000 Series A Fixed-to-Floating Rate Cumulative Redeemable Perpetual Preferred Units (the “Series A Preferred Units”) representing limited partner interests in the Partnership at a price to the public of $1,000 per unit.

The Series A Preferred Units rank senior to (i) common units representing limited partner interests in the Partnership and (ii) each other class or series of limited partner interests or other equity securities in the Partnership that may be established in the future that expressly ranks junior to the Series A Preferred Units as to the payment of distributions and amounts payable upon a liquidation event. The Series A Preferred Units rank equal in all respects with each class or series of limited partner interests or other equity securities in the Partnership that may be established in the future that is not expressly made senior or subordinated to the Series A Preferred Units as to the payment of distributions and amounts payable on a liquidation event. The Series A Preferred Units rank junior to (i) all of the Partnership’s existing and future indebtedness and other liabilities with respect to assets available to satisfy claims against the Partnership and (ii) each other class or series of limited partner interests or other equity securities in the Partnership established in the future that is expressly made senior to the Series A Preferred Units as to the payment of distributions and amounts payable upon a liquidation event. Income is allocated to the Series A Preferred Units in an amount equal to the earned distributions (whether these distributions are declared by the General Partner to be paid or not) for the respective reporting period.

Distributions on the Series A Preferred Units are cumulative and compounding and are payable semi-annually in arrears on the 15th day of each June and December through and including December 15, 2022, and, thereafter, quarterly in arrears on the 15th day of March, June, September and December of each year (each, a “Distribution Payment Date”) to holders of record as of the close of business on the first business day of the month of the applicable Distribution Payment Date, in each case, when, as, and if declared by the General Partner out of legally available funds for such purpose.

The initial distribution rate for the Series A Preferred Units is 9.50% per annum of the $1,000 liquidation preference per Series A Preferred Unit. On and after December 15, 2022, distributions on the Series A Preferred Units will accumulate for each distribution period at a percentage of the liquidation preference equal to the three-month LIBOR plus a spread of 7.43%. During the fourth quarter of 2023, distributions on the Series A Preferred Units began to accumulate at a rate equal to the three-month SOFR plus a spread of 7.69%. The floating rate established on December 15, 2023 for the period ending March 31, 2024 was 13.1%.

The Partnership suspended its distributions to be paid to holders of its Series A Preferred Units, commencing with respect to the quarter ending March 31, 2020. As of December 31, 2023, the amount of accrued and unpaid distributions on the Series A Preferred Units was $33.0 million.

A rollforward of the number of outstanding Series A Preferred Units follows for the period from December 31, 2021 to December 31, 2023.


			Series A Preferred Units
December 31, 2021			143,447
2022 Preferred Exchange Offer			(77,939)

December 31, 2022			65,508
2023 activity			—
December 31, 2023			65,508

2022 Preferred Exchange Offer. In January 2022, the Partnership completed an offer to exchange its Series A Preferred Units for newly issued common units (the “2022 Preferred Exchange Offer”), whereby it issued 2,853,875 SMLP common units, net of units withheld for withholding taxes, in exchange for 77,939 Series A Preferred Units. Upon the settlement of the 2022 Preferred Exchange Offer, the Partnership eliminated $92.6 million of the Series A Preferred Unit liquidation preference amount, inclusive of accrued distributions due as of the settlement date.

Subsidiary Series A Preferred Units. The Partnership has Subsidiary Series A Preferred Units that ranks senior to each other class or series of limited partner interests or other equity securities in Permian Holdco that may be established in the future that expressly ranks junior to the Subsidiary Series A Preferred Units as to the payment of distributions and amounts payable upon a liquidation event. The Subsidiary Series A Preferred Units rank equal in all respects with each class or series of limited partner interests or other equity securities in Permian Holdco that may be established in the future that is not expressly made senior or subordinated to the Subsidiary Series A Preferred Units as to the payment of distributions and amounts payable on a liquidation event. The Subsidiary Series A Preferred Units rank junior to (i) all of Permian Holdco’s or a subsidiary of Permian Holdco’s future indebtedness and other liabilities with respect to assets available to satisfy claims against Permian Holdco and (ii) each other class or series of limited partner interests or other equity securities in Permian Holdco established in the future that is expressly made senior to the Subsidiary Series A Preferred Units as to the payment of distributions and amounts payable upon a liquidation event. Income is allocated to the Subsidiary Series A Preferred Units in an amount equal to the earned distributions for the respective reporting period.

Distributions on the Subsidiary Series A Preferred Units are cumulative and compounding and are payable 21 days following the quarterly period ended March, June, September and December of each year (each, a “Series A Distribution Payment Date”) to holders of record as of the close of business on the first business day of the month of the applicable Series A Distribution Payment Date, in each case, when, as, and if declared by Permian Holdco out of legally available funds for such purpose.

The distribution rate for the Subsidiary Series A Preferred Units is 7.00% per annum of the $1,000 liquidation preference per Subsidiary Series A Preferred Unit. A pro-rated initial distribution on the Subsidiary Series A Preferred Units was Paid-in-kind (“PIK”) on January 21, 2020 in an amount equal to 7.00% per Subsidiary Series A Preferred Unit plus 1.00% per annum of the undrawn commitment units.

These Subsidiary Series A Preferred Units are considered redeemable securities under GAAP due to the existence of certain redemption provisions that are outside of the Partnership’s control. Therefore, the securities are classified as temporary equity in the mezzanine section of the consolidated balance sheets.

The Partnership records its Subsidiary Series A Preferred Units at fair value upon issuance, net of issuance costs, and subsequently records an effective interest method accretion amount each reporting period to accrete the carrying value to a most probable redemption value that is based on a predetermined internal rate of return measure. The Partnership also elected to make PIK distributions to holders of the Subsidiary Series A Preferred Units during portions of the year ended December 31, 2022, which increase the liquidation preference on each Subsidiary Series A Preferred Unit. Ultimately, Net Income (Loss) Attributable to common limited partners includes adjustments for PIK distributions and redemption accretion. During the year ended December 31, 2022, the Partnership issued 1,600 Subsidiary Series A Preferred Units, through PIK transactions. The Partnership did not make any PIK distributions during the year ended December 31, 2023. As of December 31, 2023 and 2022, the Partnership had 93,039 Subsidiary Series A Preferred Units outstanding.

If the Subsidiary Series A Preferred Units were redeemed on December 31, 2023, the redemption amount would be $125.5 million, when considering the applicable multiple of invested capital metric and make-whole amount provisions contained in the Amended and Restated Limited Liability Company Agreement of Permian Holdco.


	(in thousands)
Balance at January 1, 2022	$	106,325

PIK distributions	1,600

Redemption accretion, net of issuance cost amortization	15,544
Cash distribution (includes $1.6 million distributions payable as of December 31, 2022)	(4,885)
Balance at December 31, 2022	$	118,584
Redemption accretion, net of issuance cost amortization	12,581
Cash distribution (includes $1.6 million distributions payable as of December 31, 2023)	(6,513)
Balance at December 31, 2023	$	124,652

Cash Distribution Policy. The Partnership suspended its cash distributions to holders of its common units and Series A Preferred Units, commencing with respect to the quarter ending March 31, 2020. Upon the resumption of distributions, the Partnership Agreement requires that it distribute all available cash, subject to reserves established by its General Partner, within 45 days after the end of each quarter to unitholders of record on the applicable record date. The amount of distributions paid under this policy is subject to fluctuations based on the amount of cash the Partnership generates from its business and the

decision to make any distribution is determined by the General Partner, taking into consideration the terms of the Partnership Agreement.

ACQUISTIONS AND DIVESTITURES - Schedule of Fair Value of the Assets and Liabilities Acquired (Details) $ in Thousands	Dec. 01, 2022 USD ($)
Outrigger DJ
Business Acquisition [Line Items]
Consideration paid	$ 167,631
Cash	1,000
Accounts receivable	7,529
Other current assets	190
Property, plant and equipment, net	144,514
Intangible assets	21,447
Trade accounts payable, accrued expenses and other	(7,049)
Net assets acquired and liabilities assumed	167,631
Sterling DJ
Business Acquisition [Line Items]
Consideration paid	140,396
Cash	500
Accounts receivable	16,224
Other current assets	4,557
Property, plant and equipment, net	108,720
Intangible assets	38,678
Other noncurrent assets	9,865
Trade accounts payable, accrued expenses and other	(38,148)
Net assets acquired and liabilities assumed	$ 140,396

REVENUE - Schedule of Estimated Revenue Expected to be Recognized (Details) - Gathering services and related fees $ in Thousands	Dec. 31, 2023 USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 65,472
Revenue, remaining performance obligation, expected timing of satisfaction, Period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 45,594
Revenue, remaining performance obligation, expected timing of satisfaction, Period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2026-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 29,292
Revenue, remaining performance obligation, expected timing of satisfaction, Period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2027-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 7,685
Revenue, remaining performance obligation, expected timing of satisfaction, Period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2028-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 5,137
Revenue, remaining performance obligation, expected timing of satisfaction, Period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2029-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 0
Revenue, remaining performance obligation, expected timing of satisfaction, Period	1 year

ACQUISTIONS AND DIVESTITURES (Tables)

12 Months Ended

Dec. 31, 2023

Business Combination and Asset Acquisition [Abstract]

Schedule of Fair Value of the Assets and Liabilities Acquired


(in thousands)
Total consideration paid for Outrigger DJ	$	167,631
Recognized amounts of identifiable assets acquired and liabilities assumed:
Cash	1,000
Accounts receivable	7,529
Other current assets	190
Property, plant and equipment, net	144,514
Intangible assets	21,447
Trade accounts payable, accrued expenses and other	(7,049)
Net assets acquired and liabilities assumed	$	167,631

The following table sets forth the preliminary fair value of the assets acquired and liabilities assumed as of the acquisition date. There were no material changes made during 2023 to the provisional purchase accounting measurements initially recorded in December 2022 for the Sterling DJ acquisition. The purchase price allocation was complete as of the fourth quarter of 2023.


(in thousands)
Total consideration paid for Sterling DJ	$	140,396
Recognized amounts of identifiable assets acquired and liabilities assumed:
Cash	500
Accounts receivable	16,224
Other current assets	4,557
Property, plant and equipment, net	108,720
Intangible assets	38,678
Other noncurrent assets	9,865
Trade accounts payable, accrued expenses and other	(38,148)
Net assets acquired	$	140,396

Schedule of Pro Forma Information

The following table summarizes the unaudited pro forma condensed financial information of SMLP as if the acquisitions of Outrigger DJ and Sterling DJ, along with the dispositions of Bison Midstream and the Lane G&P System, had occurred on January 1, 2021:


	Year Ended December 31, 2022
Revenues	$	543,024
Net loss	$	(36,945)

SUPPLEMENTAL CASH FLOW INFORMATION (Tables)

12 Months Ended

Dec. 31, 2023

Supplemental Cash Flow Elements [Abstract]

Schedule of Supplemental Cash Flow Information


	Year ended December 31,
	2023		2022
	(In thousands)
Supplemental cash flow information:
Cash interest paid	$	127,022	$	89,472
Cash paid for taxes	15		149

Noncash investing and financing activities:
Capital expenditures in trade accounts payable (period-end accruals)	$	11,612	$	6,724
2025 Senior Notes Exchange	180,030		—
Accretion of Subsidiary Series A Preferred Units	12,581		15,544
Right-of-use assets acquired in connection with Sterling DJ acquisition	—		9,865
2022 Preferred Exchange Offer	—		92,587

REVENUE (Tables)

12 Months Ended

Dec. 31, 2023

Revenue from Contract with Customer [Abstract]

Schedule of Estimated Revenue Expected to be Recognized and MVC Shortfall Payments


	2024		2025		2026		2027		2028		Thereafter
	(in thousands)
Gathering services and related fees	$	65,472	$	45,594	$	29,292	$	7,685	$	5,137	$	—

Schedule of Disaggregated Revenue by Geographic Area and Major Products and Services Reportable Segments

In the following table, revenue is disaggregated by geographic area and major products and services. For more detailed information about reportable segments, see Note 17 -Segment Information.


	Year ended December 31, 2023
	Gathering services and related fees		Natural gas, NGLs and condensate sales		Other revenues		Total
	(in thousands)
Reportable Segments:
Northeast	$	63,805	$	—	$	—	$	63,805
Rockies	65,869		173,688		15,474		255,031
Permian	—		—		3,570		3,570
Piceance	81,041		4,788		5,588		91,417
Barnett	37,508		778		6,831		45,117
Total reportable segments	248,223		179,254		31,463		458,940
Corporate and other	—		—		(37)		(37)

Total	$	248,223	$	179,254	$	31,426	$	458,903


	Year ended December 31, 2022
	Gathering services and related fees		Natural gas, NGLs and condensate sales		Other revenues		Total
	(in thousands)
Reportable Segments:
Northeast	$	54,392	$	—	$	—	$	54,392
Rockies	67,838		59,208		16,557		143,603
Permian	3,668		17,382		4,101		25,151
Piceance	80,630		7,111		5,608		93,349
Barnett	41,830		2,503		7,763		52,096
Total reportable segments	248,358		86,204		34,029		368,591
Corporate and other	—		21		982		1,003
Total	$	248,358	$	86,225	$	35,011	$	369,594

ACQUISTIONS AND DIVESTITURES - Schedule of Pro Forma Information (Details)	12 Months Ended
	Dec. 31, 2022 USD ($)
Business Combination and Asset Acquisition [Abstract]
Revenues	$ 543,024
Net loss	$ (36,945)

EARNINGS PER UNIT (Tables)

12 Months Ended

Dec. 31, 2023

Earnings Per Share [Abstract]

Schedule of Earnings Per Limited Partner Unit

The following table details the components of EPU.


	Year ended December 31,
	2023		2022
	(In thousands, except per-unit amounts)
Numerator for basic and diluted EPU:
Allocation of net loss among limited partner interests:
Net loss	$	(38,947)	$	(123,461)
Less: Net income attributable to Subsidiary Series A Preferred Units	(12,581)		(17,144)

Net loss attributable Summit Midstream Partners, LP	(51,528)		(140,605)

Less: Net income attributable to Series A Preferred Unit	(11,566)		(8,048)
Add: Deemed capital contribution	—		20,974
Net loss attributable to common limited partners	$	(63,094)	$	(127,679)

Denominator for basic and diluted EPU:
Weighted-average common units outstanding – basic	10,334		10,048
Effect of nonvested phantom units	—		—
Weighted-average common units outstanding – diluted	10,334		10,048

Net Loss per limited partner unit:
Common unit – basic	$	(6.11)	$	(12.71)
Common unit – diluted	$	(6.11)	$	(12.71)

Nonvested anti-dilutive phantom units excluded from the calculation of diluted EPU	245		177

DEBT - Schedule of Maturities (Details) $ in Thousands	Dec. 31, 2023 USD ($)
Debt Disclosure [Abstract]
2024	$ 15,524
2025	66,363
2026	1,324,477
2027	17,769
2028	78,006
Thereafter	0
Total	$ 1,502,139

EARNINGS PER UNIT (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net loss	$ (38,947)	$ (123,461)
Net loss attributable to Summit Midstream Partners, LP	(51,528)	(140,605)
Parent Company
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Add: deemed capital contribution	$ 0	$ 20,974
Phantom Units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Nonvested anti-dilutive phantom units excluded from the calculation of diluted EPU (in shares)	245	177
Series A Preferred Units \| Subsidiaries
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Less: Net income attributable to Subsidiary Series A Preferred Units	$ (12,581)	$ (17,144)
Series A Preferred Units \| Parent Company
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Less: Net income attributable to Subsidiary Series A Preferred Units	(11,566)	(8,048)
Common units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net income (loss) attributable to limited partners	$ (63,094)	$ (127,679)
Weighted-average common units outstanding – basic (in shares)	10,334	10,048
Effect of nonvested phantom units (in shares)	0	0
Weighted-average common units outstanding – diluted (in shares)	10,334	10,048
Common unit - basic (in dollars per share)	$ (6.11)	$ (12.71)
Common unit - diluted (in dollars per share)	$ (6.11)	$ (12.71)