Schedule Of Partner Units Activity Schedule Of Partner Units Activity Table [Table Text Block] Schedule of partner units activity. Supplemental cash flow information: Supplemental Cash Flow Information [Abstract] Double E Double E Company L L C [Member] Double E company. Fair Value Hierarchy and NAV Fair Value Hierarchy and NAV [Domain] Net income (loss) attributable to Summit Midstream Partners, LP Net income (loss) attributable to Summit Midstream Partners, LP Net Income (Loss) Attributable to Parent Noncurrent accrued environmental remediation Accrued Environmental Loss Contingencies, Noncurrent Consolidated Entities Consolidated Entities [Axis] Entity Emerging Growth Company Entity Emerging Growth Company Common units issued in exchange (in shares) Common Unit, Issued Common units issued for SMLP LTIP, net (in shares) Partners' Capital Account, Unit-based Payment Arrangement, Number of Units Statistical Measurement Statistical Measurement [Domain] Transaction costs Business Combination, Acquisition Related Costs Entity Address, Address Line One Entity Address, Address Line One Entity Address, Address Line Two Entity Address, Address Line Two Accrued and unpaid distributions Accrued and Unpaid Distributions Accrued and Unpaid Distributions Natural gas, NGLs and condensate sales Oil and Condensate [Member] Revenue from Contract with Customer [Abstract] Revenue from Contract with Customer [Abstract] Contract with Customer, Contract Asset, Contract Liability, and Receivable Contract with Customer, Contract Asset, Contract Liability, and Receivable [Table Text Block] Entity Filer Category Entity Filer Category Other noncurrent assets Other Assets, Noncurrent Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Investment, Name Investment, Name [Axis] Segments Segments [Axis] Interest Rate Swaps Derivatives, Policy [Policy Text Block] Units remaining available (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Net change in cash, cash equivalents and restricted cash Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Redemption price, expressed as percentage of principal amount Debt Instrument, Redemption Price, Percentage Gain on repurchases of Senior Notes Gain (Loss) on Repurchase of Debt Instrument PIK Distributions PIK Distributions [Member] PIK Distributions Gain on asset sales, net Gain on asset sales, net Gain (Loss) on Disposition of Assets Document Fiscal Year Focus Document Fiscal Year Focus Subsequent Event Type Subsequent Event Type [Domain] Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] Debt issuance costs Payments of Financing Costs Long-lived asset impairments Impairment of Long-Lived Assets to be Disposed of Nonvested anti-dilutive phantom units excluded from the calculation of diluted EPU (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Contract with customer, liability, revenue recognized Contract with Customer, Liability, Revenue Recognized Common Units Common Units [Member] Common unit. Subsequent Events [Abstract] Subsequent Events [Abstract] Cash, Cash Equivalents and Restricted Cash Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block] Stock split, conversion ratio Stockholders' Equity Note, Stock Split, Conversion Ratio Grant date fair value (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Commitment fee (as a percent) Line of Credit Facility, Commitment Fee Percentage Business Acquisition Business Acquisition [Axis] Net income (loss) attributable to limited partners Net income (loss) attributable to limited partners Net Income (Loss) Allocated to Limited Partners Loss Contingency, Loss in Period Loss Contingency, Loss in Period Accrued interest Increase (Decrease) in Interest Payable, Net Principal Owner Principal Owner [Member] Award Type Award Type [Domain] Credit Facility Credit Facility [Domain] ASSETS Assets [Abstract] Barnett Shale Barnett Shale Segment [Member] Barnett Shale segment. Segment Reconciling Items Segment Reconciling Items [Member] Restructuring costs Restructuring Costs Granted units (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Entity Address, City or Town Entity Address, City or Town Interest in partnership per unit (in dollars per share) Shares Issued, Price Per Share Debt Instrument Debt Instrument [Axis] Summit Midstream Partners Holdings L L C Summit Midstream Partners Holdings L L C [Member] Summit Midstream Partners Holdings, LLC. COMMITMENTS AND CONTINGENCIES Commitments and Contingencies Disclosure [Text Block] 2025 Senior Notes Senior Notes Due2025 [Member] Senior Notes due 2025 Energy Capital Partners Energy Capital Partners [Member] Energy Capital Partners. DJ Basin D J Basin Segment [Member] DJ Basin. Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Related Party Related Party [Axis] Distributions from equity method investees June cash distributions Proceeds from Equity Method Investment, Distribution Accounts receivable Increase (Decrease) in Accounts Receivable Schedule of Accrued Environmental Remediation Schedule of Environmental Loss Contingencies by Site [Table Text Block] Capital expenditures in trade accounts payable (period-end accruals) Capital Expenditures Incurred but Not yet Paid Meadowlark Midstream Gathering System Meadowlark Midstream Gathering System [Member] Meadowlark Midstream gathering system. Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] Net income (loss) Profit Loss Excluding Subsidiary Income Profit loss excluding subsidiary income. 2022 Senior Notes Senior Notes Due2022 [Member] Senior Notes due 2022. Proceeds from issuance of Subsidiary Series A preferred units, net of issuance costs Proceeds from Issuance of Preferred Limited Partners Units Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Entity Interactive Data Current Entity Interactive Data Current Unused portion under the facility Line of Credit Facility, Remaining Borrowing Capacity REVENUE Revenue from Contract with Customer [Text Block] Organization And Business Operations [Line Items] Organization And Business Operations [Line Items] Organization and business operations. Unit-based compensation Partners' Capital Account, Unit-based Payment Arrangement, Amount Document Type Document Type OGC Ohio Gathering Company L L C [Member] Ohio Gathering Company, L.L.C. Partners Capital [Table] Partners Capital [Table] Partners' capital. Schedule of Disaggregated Revenue by Geographic Area and Major Products and Services Reportable Segments Disaggregation of Revenue [Table Text Block] Fair Value Measurement Fair Value Measurement [Domain] Unsettled loss on interest rate swaps Unrealized Gain (Loss) on Derivatives Entity Current Reporting Status Entity Current Reporting Status Preferred units, outstanding (in shares) Subsidiary Series A preferred unitholders, outstanding (in shares) Preferred Units, Outstanding Additions Contract With Customer Asset Additions Contract with customer asset, additions. Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Plan Name Plan Name [Axis] Expected payment Accrual for Environmental Loss Contingencies, Expected Payment Accrual for Environmental Loss Contingencies, Expected Payment Ratio of consolidated trailing 12-month EBITDA to net interest expense Ratio Of Consolidated Trailing12month E B I T D A To Net Interest Expense Ratio of consolidated trailing 12month EBITDA to net interest expense. Total debt Long-term Debt Cash flows from investing activities: Net Cash Provided by (Used in) Investing Activities [Abstract] Document Transition Report Document Transition Report Beginning balance Ending balance Partners' Capital Interest cost capitalized Interest Paid, Capitalized, Investing Activities Permian Basin Permian Basin Segment [Member] Permian Basin segment member. TOTAL LIABILITIES AND CAPITAL Liabilities and Equity SMLP common units pledged as collateral under the SMPH Term Loan (in shares) Common Units Pledged As Collateral Common units pledged as collateral. Adjusted EBITDA Total of reportable segments' measures of profit Adjusted Earnings Before Interest Taxes Depreciation And Amortization Adjusted earnings before interest, taxes, depreciation, and amortization. Gathering and processing systems and related equipment Gas Gathering and Processing Equipment [Member] Deferred revenue Current deferred revenue, beginning balance Current deferred revenue, ending balance Contract with Customer, Liability, Current Scenario [Axis] Scenario [Axis] Debt issuance costs Debt Issuance Cost, Gross, Noncurrent Restricted cash Restricted Cash SMLP LTIP Long Term Incentive Plan [Member] Long-term incentive plan. Series A Preferred Unit Exchange Offer, net of shares withheld for taxes (in shares) Partners' Capital Account, Units, Converted Supplemental Cash Flow Elements [Abstract] Supplemental Cash Flow Elements [Abstract] Common limited partner capital (6,744,926 and 6,110,092 units issued and outstanding at June 30, 2021 and December 31, 2020, respectively) Limited Partners' Capital Account Concentration Risk [Line Items] Concentration Risk [Line Items] LIABILITIES AND CAPITAL Liabilities and Equity [Abstract] Corporate and Other expense Corporate And Other Expenses Corporate and other expenses. Environmental Remediation Site Environmental Remediation Site [Axis] Interest Rate Swap Interest Rate Swap [Member] EARNINGS PER UNIT Earnings Per Share [Text Block] Percentage of ownership interest Equity Method Investment, Ownership Percentage Schedule of Information about Contract Assets from Contracts with Customers Schedule Of Contract With Customer Asset Table [Table Text Block] Schedule of contract with customer, asset. Minimum Minimum [Member] Redemption amount Preferred Stock, Redemption Amount ORGANIZATION, BUSINESS OPERATIONS AND PRESENTATION AND CONSOLIDATION Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Reconciliation of Assets from Segment to Consolidated Reconciliation of Assets from Segment to Consolidated [Table Text Block] Other, net Increase (Decrease) in Other Operating Assets and Liabilities, Net Tax withholdings and associated payments on vested SMLP LTIP awards Partners Capital Account Tax Withholding For Unit Based Compensation Partners' capital account tax withholding for unit-based compensation. Secured notes Long-term Line of Credit Common unit - diluted (in dollars per share) Net Income (Loss), Net of Tax, Per Outstanding Limited Partnership Unit, Diluted Common units issued prior to reverse unit split (in shares) Stock Issued During Period, Shares, Reverse Stock Splits Income (loss) before income taxes and equity method investment income Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest Less unamortized debt issuance costs Deferred issuance costs Debt Issuance Costs, Net Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Proceeds from asset sale Proceeds from Sale of Productive Assets Subsidiary Subsidiaries Subsidiaries [Member] Add: deemed contribution from 2021 Preferred Exchange Offer Deemed contribution to common unit holders Contributed Capital From Preferred Units Exchange Contributed Capital From Preferred Units Exchange Common units - basic (in shares) Weighted-average common units outstanding – basic (in shares) Weighted Average Limited Partnership Units Outstanding, Basic Series A Preferred Units Series A Preferred Units [Member] Series A preferred units. Trading Symbol Trading Symbol Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Table Text Block] Common limited partner capital (in shares), outstanding Common limited partner capital (in shares) Limited Partners' Capital Account, Units Outstanding Accrued compensation and employee benefits Accrued Employee Benefits, Current Maximum period following end of quarter to distribute all available cash Distribution Of All Available Cash Maximum Period Following End Of Quarter Distribution of all available cash, maximum period following end of quarter. ECP Holdings Warrant E C P Holdings Warrant [Member] ECP holdings warrant. General and administrative General and Administrative Expense SUPPLEMENTAL CASH FLOW INFORMATION Cash Flow, Supplemental Disclosures [Text Block] Revision of Prior Period [Axis] Revision of Prior Period [Axis] Restructuring Plan [Domain] Restructuring Plan [Domain] DEBT Debt Disclosure [Text Block] Debt default amount Debt Instrument, Debt Default, Amount UNIT-BASED AND NONCASH COMPENSATION Share-based Payment Arrangement [Text Block] Warrant issuance for GP Buy-In Transaction Warrants Issued For Buy-In Transaction Warrants Issued For Buy-In Transaction Accounting Policies [Abstract] Accounting Policies [Abstract] Derivative Instrument Derivative Instrument [Axis] Term Loan Credit Facility Term Loan Credit Facility [Member] Term loan credit facility. Partner Type of Partners' Capital Account, Name Partner Type of Partners' Capital Account, Name [Domain] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Commitments and contingencies (Note 13) Commitments and Contingencies Subsequent Event [Table] Subsequent Event [Table] Gathering services and related fees Gathering Services And Related Fees [Member] Gathering services and related fees. 2019 Restructuring Activities Two Thousand Nineteen Restructuring Activities [Member] 2019 restructuring activities member Double E Double E Pipeline L L C [Member] Double E Pipeline, LLC. Partner Capital Components Partner Capital Components [Domain] Debt issue costs Payments of Debt Issuance Costs Statement of Partners' Capital [Abstract] Statement of Partners' Capital [Abstract] Borrowings under ECP Loans Proceeds from Issuance of Debt Document Period End Date Document Period End Date Effect of nonvested phantom units (in shares) Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Total costs and expenses Costs and Expenses Class of Stock Class of Stock Class of Stock [Axis] Entity Registrant Name Entity Registrant Name Add: additions Contract With Customer Liability, Noncurrent, Additions Contract with customer liability noncurrent additions. Treasury stock (in shares) Treasury Stock, Shares Contract with Customer, Contract Asset, Contract Liability, and Receivable [Abstract] Contract with Customer, Contract Asset, Contract Liability, and Receivable [Abstract] Type of Cost, Good or Service [Extensible List] Cost, Product and Service [Extensible Enumeration] Partners' leverage ratio Debt Instrument, Covenant, Leverage Ratio Debt Instrument, Covenant, Leverage Ratio Add: additions Contract With Customer Liability, Current, Additions Contract with customer liability current additions. Ratio of first lien net indebtedness to consolidated trailing 12-month EBITDA Ratio Of First Lien Net Indebtedness To Consolidated Trailing12 Month E B I T D A Ratio of first lien net indebtedness to consolidated trailing 12 month EBITDA. Subsidiary Series A Preferred Units (88,321 and 85,308 units issued and outstanding at June 30, 2021 and December 31, 2020, respectively) Temporary Equity, Carrying Amount, Attributable to Parent Number of common units purchased (in shares) Business Acquisition, Equity Interest Issued or Issuable, Number of Shares Accrued expenses Accrued and unpaid liabilities Accrued Liabilities, Current Total revenues Revenue from Contract with Customer, Excluding Assessed Tax Damages Payable To Federal Government over Five Years Damages Payable To Federal Government over Five Years [Member] Damages Payable To Federal Government over Five Years Purchase of common units in GP Buy-In Transaction Payments To Acquire Common Units Payments To Acquire Common Units Adjustments related to MVC shortfall payments Adjustments Related To Minimum Volume Commitments Shortfall Payments Adjustments related to minimum volume commitments shortfall payments. Equity [Abstract] Equity [Abstract] Fair Value Hierarchy and NAV Fair Value Hierarchy and NAV [Axis] Carrying Value Reported Value Measurement [Member] Consolidation Items Consolidation Items [Domain] Loss on ECP Warrants Fair Value Adjustment of Warrants Change in Contract with Customer, Liability, Current [Roll Forward] Change in Contract with Customer, Liability, Current [Roll Forward] Change in Contract with Customer, Liability, Current Utica Shale Utica Shale Segment [Member] Utica Shale segment. Variable Rate Variable Rate [Axis] Effect of 2021 Preferred Exchange Offer, inclusive of an $8.3 million deemed contribution to common unit holders (Note 9) Partners' Capital Account, Exchanges and Conversions SEGMENT INFORMATION Segment Reporting Disclosure [Text Block] Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Common units not pledged as collateral (in shares) Common Units Not Pledged As Collateral Common units not pledged as collateral. Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] 2022 Senior Notes: Summit Holdings' 5.5% senior unsecured notes due August 15, 2022 Five Point Five Percent Two Thousand Twenty Two Senior Notes [Member] 5.5% 2022 Senior Notes Property, Plant and Equipment [Abstract] Property, Plant and Equipment [Abstract] Unit-based and noncash compensation Share-based Payment Arrangement, Noncash Expense RESTRUCTURING Restructuring and Related Activities Disclosure [Text Block] Variable Rate Variable Rate [Domain] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Depreciation expense Depreciation Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Effect of common unit issuances under SMLP LTIP Partners' Capital Account, Sale of Units Tax withholdings on 2021 Preferred Exchange Offer Partners' Capital, Decrease From Tax Withholding From Preferred Stock Exchange Partners' Capital, Decrease From Tax Withholding From Preferred Stock Exchange Accrued expenses Increase (Decrease) in Accrued Liabilities Loss on ECP Warrants Gain (Loss) on Derivative Instruments, Net, Pretax Cash paid for taxes Income Taxes Paid Environmental Remediation Site Environmental Remediation Site [Domain] Marcellus Shale Marcellus Shale Segment [Member] Marcellus Shale segment. Partners Capital [Line Items] Partners Capital [Line Items] Partners' capital. Other, net Payments for (Proceeds from) Other Investing Activities Reconciliation Of Net Income To Adjusted EBITDA Reconciliation Of Net Income To Adjusted E B I T D A Table [Table Text Block] Reconciliation of net income to adjusted EBITDA. Additional accruals Accrual for Environmental Loss Contingencies, Period Increase (Decrease) Capital expenditures Payments to Acquire Property, Plant, and Equipment Credit Agreement Credit Agreement [Member] Credit agreement. Other current liabilities Other Liabilities, Current Net cash distributions to SMLP unitholders Partners' Capital Account, Distributions PARTNERS' CAPITAL AND MEZZANINE CAPITAL Partners' Capital Notes Disclosure [Text Block] Interest rate at period end Line of Credit Facility, Interest Rate at Period End Maximum Maximum [Member] Share-based Payment Arrangement [Abstract] Share-based Payment Arrangement [Abstract] Loss Contingency, Nature [Domain] Loss Contingency, Nature [Domain] DEFERRED REVENUE Contract With Customer Liability Disclosure [Text Block] Contract with customer liability disclosure. Total liabilities Liabilities Legal Entity Legal Entity [Axis] Natural gas, NGLs and condensate sales Natural Gas N G L And Condensate Sales [Member] Natural gas, NGLs and condensate sales. Award Type Award Type [Axis] Cash flows from financing activities: Net Cash Provided by (Used in) Financing Activities [Abstract] Consolidation Items Consolidation Items [Axis] EQUITY METHOD INVESTMENTS Equity Method Investments and Joint Ventures Disclosure [Text Block] Schedule of Cash Flow, Supplemental Disclosures Schedule of Cash Flow, Supplemental Disclosures [Table Text Block] Partner Capital Components Partner Capital Components [Axis] Repurchase of Senior Notes Repayments of Senior Debt Gain on early extinguishment of debt Gain on extinguishment of debt Gain on early extinguishment of debt Gain (Loss) on Extinguishment of Debt Noncash investing and financing activities: Noncash Investing and Financing Items [Abstract] Redemption accretion Accretion of Subsidiary Series A Preferred Units Preferred Stock, Accretion of Redemption Discount Interest expense Interest expense Interest Expense Proceeds from asset sale Proceeds From Sale Of Assets Proceeds from sale of assets. Interest rate during period (as a percent) Debt Instrument, Interest Rate, Effective Percentage 2025 Senior Notes: Summit Holdings' 5.75% senior unsecured notes due April 15, 2025 Five Point Seven Five Percent Two Thousand Twenty Five Senior Notes [Member] 5.75% 2022 Senior Notes. Loss Contingency Nature [Axis] Loss Contingency Nature [Axis] Depreciation and amortization Depreciation Depletion And Amortization Including Amortization Of Above And Below Market Leases Depreciation depletion and amortization including amortization of above and below market leases. City Area Code City Area Code Reportable Segments Operating Segments [Member] Litigation Case [Domain] Litigation Case [Domain] Ad valorem taxes payable Accrual for Taxes Other than Income Taxes, Current Commitment fee on unused portion of the facility Line of Credit Facility, Unused Capacity, Commitment Fee Percentage Revision of Prior Period [Domain] Revision of Prior Period [Domain] Equity Method Investments Equity Method Investments [Table Text Block] Reconciliation of Revenue from Segments to Consolidated Reconciliation of Revenue from Segments to Consolidated [Table Text Block] Condensed Financial Statements [Table] Condensed Financial Statements [Table] GP Buy-In GP Buy-In [Member] GP Buy-In Income Statement [Abstract] Income Statement [Abstract] Investment in equity method investees Ending balance Beginning balance Equity method investment Equity Method Investments Amendment Flag Amendment Flag Concentration Risk [Table] Concentration Risk [Table] Revolving credit facility Secured Long-term Debt, Noncurrent Fair Value Estimate of Fair Value Measurement [Member] Partner Type Partner Type [Axis] Repayments on Revolving Credit Facility Repayments of Lines of Credit Senior notes Notes Payable, Fair Value Disclosure Schedule of Gain (Loss) on Extinguishment of Debt Schedule of Gain (Loss) on Extinguishment of Debt [Table Text Block] Schedule of Gain (Loss) on Extinguishment of Debt Income tax benefit Income Tax Expense (Benefit) Accounts receivable, net Accounts Receivable, after Allowance for Credit Loss, Current Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Total current assets Assets, Current Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Schedule of Stock by Class [Table] Schedule of Stock by Class [Table] Contract With Customer, Contract Asset, Contract Liability, and Receivable [Roll Forward] Contract With Customer, Contract Asset, Contract Liability, and Receivable [Roll Forward] Contract With Customer, Contract Asset, Contract Liability, and Receivable Fair value, other assets Other Assets, Fair Value Disclosure Entity File Number Entity File Number Piceance Basin Piceance Basin Segment [Member] Piceance Basin segment. Equity Method Investments and Joint Ventures [Abstract] Equity Method Investments and Joint Ventures [Abstract] Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Ohio Gathering Ohio Gathering Segment [Member] Ohio Gathering segment. Accrued environmental remediation Accrued Environmental Loss Contingencies, Current Less: reclassification to current deferred revenue Contract With Customer Liability, Noncurrent, Reclassification To Current Contract with customer liability noncurrent reclassification to current. Current portion of long-term debt Revolving Credit Facility Long-term Debt, Current Maturities Product and Service [Axis] Product and Service [Axis] Long-Lived Tangible Asset Long-Lived Tangible Asset [Domain] Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Grant date fair value (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Weighted Average Grant Date Fair Value Entity Small Business Entity Small Business Restructuring Plan [Axis] Restructuring Plan [Axis] Asset Backed Revolving Credit Facility Asset Backed Revolving Credit Facility [Member] Asset Backed Revolving Credit Facility Natural Resource Damages To Federal and State Governments Natural Resource Damages To Federal and State Governments [Member] Natural Resource Damages To Federal and State Governments Issued units (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period Increase (Decrease) in Partners' Capital [Roll Forward] Increase (Decrease) in Partners' Capital [Roll Forward] Schedule of Equity Method Investments [Table] Schedule of Equity Method Investments [Table] Penalties and fines, payment period Environmental Loss Contingencies, Penalties and Fines, Payment Period Environmental Loss Contingencies, Penalties and Fines, Payment Period Land and line fill Landand Line Fill [Member] Land and line fill. Statement [Line Items] Statement [Line Items] Litigation Case [Axis] Litigation Case [Axis] Limited Partners' Capital Account, Class Limited Partners' Capital Account, Class [Domain] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Deferred revenue, net Increase (Decrease) in Contract with Customer, Liability Revenue, remaining performance obligation, amount Revenue, Remaining Performance Obligation, Amount Schedule of Carrying Values and Estimated Fair Values of Debt Instruments Schedule of Carrying Values and Estimated Fair Values of Debt Instruments [Table Text Block] Debt Disclosure [Abstract] Debt Disclosure [Abstract] Entity Address, State or Province Entity Address, State or Province Estimated fair value (Level 2) Fair Value, Inputs, Level 2 [Member] Other Other Capitalized Property Plant and Equipment [Member] Revenue From Contract With Customer [Line Items] Revenue From Contract With Customer [Line Items] Revenue from contract with customer. PIK distributions Dividends, Preferred Stock, Paid-in-kind Long-Lived Tangible Asset Long-Lived Tangible Asset [Axis] Noncurrent deferred revenue Noncurrent deferred revenue, beginning balance Noncurrent deferred revenue, ending balance Contract with Customer, Liability, Noncurrent Total partners' capital Beginning balance Ending balance Partners' Capital, Including Portion Attributable to Noncontrolling Interest Corporate and Other Corporate, Non-Segment [Member] Segment Reporting [Abstract] Segment Reporting [Abstract] Unsecured notes Unsecured Long-term Debt, Noncurrent Entity Entity [Domain] Revenue From Contract With Customer [Table] Revenue From Contract With Customer [Table] Revenue from contract with customer. Restructuring Cost and Reserve [Line Items] Restructuring Cost and Reserve [Line Items] Mezzanine Capital Temporary Equity [Abstract] Use of Estimates Use of Estimates, Policy [Policy Text Block] Trade accounts payable Increase (Decrease) in Accounts Payable, Trade Schedule of Earnings Per Share, Basic and Diluted Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Entity Shell Company Entity Shell Company Local Phone Number Local Phone Number Forecast Forecast [Member] Common units - diluted (in shares) Weighted-average common units outstanding – diluted (in shares) Weighted Average Limited Partnership Units Outstanding, Diluted TOTAL ASSETS Assets Assets Investment, Name Investment, Name [Domain] Plan Name Plan Name [Domain] Net cash distributions to noncontrolling interest SMLP unitholders Payments to Noncontrolling Interests Repayments on SMPH Term Loan Repayments of Secured Debt Repurchase of common units under GP Buy-In Transaction Partners Capital Account, Decrease From Repurchase of Common Units Partners Capital Account, Decrease From Repurchase of Common Units Other Partners' Capital, Other Common Noncontrolling Interest Common Noncontrolling Interests [Member] Common noncontrolling interests. Noncontrolling Interest Noncontrolling Interest [Member] Product and Service Product and Service [Domain] Stated interest rate (as a percent) Debt Instrument, Interest Rate, Stated Percentage Derivative Contract Derivative Contract [Domain] Net loss attributable to noncontrolling interest Net Income (Loss) Attributable to Noncontrolling Interest Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Revolving credit facility Revolving Credit Facility [Member] 2025 Senior Notes Two Thousand Twenty Five Senior Notes [Member] Two thousand twenty five senior notes. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES AND RECENTLY ISSUED ACCOUNTING STANDARDS APPLICABLE TO THE PARTNERSHIP Significant Accounting Policies [Text Block] Revenue, remaining performance obligation, expected timing of satisfaction Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period SMP Holdings S M P Holdings [Member] SMP Holdings. 2022 Senior Note Two Thousand Twenty Two Senior Notes [Member] Two thousand twenty two senior notes member. Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities Subsidiary Series A preferred unitholders, issued (in shares) Preferred units issued (in shares) Preferred Units, Issued Derivative liability, notional amount Derivative Liability, Notional Amount Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Entity Tax Identification Number Entity Tax Identification Number Subsequent Event [Line Items] Subsequent Event [Line Items] Segments Segments [Domain] Noncash lease expense Operating Lease, Right-of-Use Asset, Amortization Expense Debt discharge and restructuring Consideration For Consensual Debt Discharge And Restructuring Consideration for a consensual debt discharge and restructuring. SUBSEQUENT EVENTS Subsequent Events [Text Block] Unused portion of the Permian Transmission Credit facility Debt Instrument, Unused Borrowing Capacity, Amount Schedule of Restructuring and Related Costs [Table] Schedule of Restructuring and Related Costs [Table] Receivables with customers Unbilled Contracts Receivable Net cash provided by (used in) financing activities Net Cash Provided by (Used in) Financing Activities Weighted-average limited partner units outstanding: Weighted Average Number of Shares Outstanding, Diluted [Abstract] Vesting period Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Net income (loss) per limited partner unit: Net Income (Loss), Per Outstanding Limited Partnership Unit, Basic, Net of Tax [Abstract] Income from equity method investees Income from equity method investees Income (Loss) from Equity Method Investments Business Acquisition, Acquiree Business Acquisition, Acquiree [Domain] FINANCIAL INSTRUMENTS Fair Value Disclosures [Text Block] Trade accounts payable Accounts Payable, Current Depreciation and amortization Depreciation, Depletion and Amortization Summit Investments Summit Investments [Member] Summit investments. Borrowings under Revolving Credit Facility Proceeds from Long-term Lines of Credit GP Buy-In Transaction assumption of noncontrolling interest in SMLP Partners Capital Account, Increase From Assumption of Noncontrolling Interest Partners Capital Account, Increase From Assumption of Noncontrolling Interest Contract assets, beginning of period Contract assets, end of period Contract assets included in accounts receivable Contract with Customer, Asset, after Allowance for Credit Loss Schedule Of Depreciation Expense And Capitalized Interest Costs Table Text Block Schedule Of Depreciation Expense And Capitalized Interest Costs Table [Table Text Block] Tabular disclosure of depreciation expense related to the property, plant and equipment and capitalized interest costs. Other income (expense), net Other Operating Income (Expense), Net Organization And Business Operations [Table] Organization And Business Operations [Table] Disclosure pertaining to organization and business operations. Cost of natural gas and NGLs Cost of Goods and Services Sold Revenues: Revenues [Abstract] Restructuring and Related Activities [Abstract] Restructuring and Related Activities [Abstract] Increase (Decrease) In Equity Method Investments [Roll Forward] Increase (Decrease) In Equity Method Investments [Roll Forward] Increase (Decrease) In Equity Method Investments Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Schedule of Estimated Revenue Expected to be Recognized and MVC Shortfall Payments Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table Text Block] Other revenues Product and Service, Other [Member] Consolidated Entities Consolidated Entities [Domain] Unpaid penalties and fines, fixed rate (as a percent) Accrual for Environmental Loss Contingencies, Discount Rate Property, Plant and Equipment Property, Plant and Equipment [Table Text Block] Working Capital Credit Facility Working Capital Credit Facility [Member] Working Capital Credit Facility. Capitalized interest Capitalized Interest Costs, Including Allowance for Funds Used During Construction Debt instrument term Debt Instrument, Term Payments made Accrual for Environmental Loss Contingencies, Payments Loss Contingencies [Line Items] Loss Contingencies [Line Items] Condensed Financial Statements, Captions [Line Items] Condensed Financial Statements, Captions [Line Items] Property, plant and equipment, net Property, plant and equipment, net Property, Plant and Equipment, Net PROPERTY, PLANT, AND EQUIPMENT Property, Plant and Equipment Disclosure [Text Block] Other noncurrent liabilities Other Liabilities, Noncurrent Change in Contract with Customer, Liability, Noncurrent [Roll Forward] Change in Contract with Customer, Liability, Noncurrent [Roll Forward] Change in Contract with Customer, Liability, Noncurrent Schedule of Debt Schedule of Long-term Debt Instruments [Table Text Block] Debt Instrument [Line Items] Debt Instrument [Line Items] Earnings Per Share [Abstract] Earnings Per Share [Abstract] Total Property, Plant and Equipment, Gross Document Quarterly Report Document Quarterly Report Partners' Capital Partners Capital [Member] Partners capital. Exercise price of warrants (in dollars per share) Class of Warrant or Right, Exercise Price of Warrants or Rights Williston Basin Williston Basin Segment [Member] Williston Basin segment. Borrowing capacity Line of Credit Facility, Current Borrowing Capacity Operation and maintenance Utilities Operating Expense, Maintenance and Operations Line of Credit Facility [Table] Line of Credit Facility [Table] Less: revenue recognized Contract With Customer Liability, Current, Revenue Recognized Contract with customer liability current revenue recognized. 2020 Restructuring Activities Two Thousand Twenty Restructuring Activities [Member] 2020 restructuring activities member Loss contingency accrual Loss Contingency Accrual Proportional adjusted EBITDA for equity method investees Adjusted Earnings Before Interest Taxes Depreciation And Amortization Proportional Equity Method Investment Adjustment Adjusted earnings before interest, taxes, depreciation, and amortization, proportional equity method investment adjustment. Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Costs and expenses: Costs and Expenses [Abstract] Basis difference Equity Method Investment Amortizationof Difference Between Carrying Amountand Underlying Equity Equity method investment, amortization of difference between carrying amount and underlying equity. Long-term debt, excluding current portion Long-term Debt, Excluding Current Maturities Revolving Credit Facility: Summit Holdings' variable rate senior secured revolving credit facility due May 13, 2022 Senior Notes Due May Twenty Twenty Two [Member] Senior notes due may twenty twenty two. Schedule of Equity Method Investments [Line Items] Schedule of Equity Method Investments [Line Items] Accrual for Environmental Loss Contingencies [Roll Forward] Accrual for Environmental Loss Contingencies [Roll Forward] Document Fiscal Period Focus Document Fiscal Period Focus Series A Preferred Units Series A Preferred Stock Series A Preferred Stock [Member] Number of directors Number Of Directors Number of directors. Net income (loss) Net income (loss) Net income (loss) Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Amortization of debt issuance costs Amortization of Debt Issuance Costs Construction in progress Construction in Progress [Member] Cash, cash equivalents and restricted cash, beginning of period Cash, cash equivalents and restricted cash, end of period Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Common Units Limited Partner Common Units [Member] Limited partner common units. Summit Holdings And Finance Corporation Summit Holdings And Finance Corporation [Member] Summit Holdings and Finance Corporation. Limited Partners' Capital Account by Class Limited Partners' Capital Account by Class [Axis] Other, net Proceeds from (Payments for) Other Financing Activities Entity Central Index Key Entity Central Index Key Units, beginning balance (in shares) Units, ending balance (in shares) Partners' Capital Account, Units Common limited partner capital (in shares), issued Limited Partners' Capital Account, Units Issued LIBOR London Interbank Offered Rate (LIBOR) [Member] Security Exchange Name Security Exchange Name Adjustments related to capital reimbursement activity Adjustments Related To Capital Reimbursement Activity Adjustments related to capital reimbursement activity. Valuation of warrants Warrants and Rights Outstanding Accrued interest Interest Payable, Current Related Party Related Party [Domain] Current Fiscal Year End Date Current Fiscal Year End Date Applicable margin Debt Instrument, Basis Spread on Variable Rate Measurement Basis Measurement Basis [Axis] Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Accrued environmental remediation, net Increase (Decrease) in Regulatory Liabilities Investment in Double E equity method investee Investment in equity method investment Payments to Acquire Equity Method Investments Damages Payable To State Governments Over Six Years Damages Payable To State Governments Over Six Years [Member] Damages Payable To State Governments Over Six Years Class of Stock [Line Items] Class of Stock [Line Items] Credit Facility Credit Facility [Axis] Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities Cash interest paid Interest Paid, Including Capitalized Interest, Operating and Investing Activities Portion at Fair Value Measurement Portion at Fair Value Measurement [Member] Changes in operating assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Less: accumulated depreciation Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Series A Preferred Units (143,447 and 162,109 units issued and outstanding at June 30, 2021 and December 31, 2020, respectively) Preferred Units, Preferred Partners' Capital Accounts Additional debt issuance Debt Instrument, Covenant, Capacity Threshold, Additional Debt Issuance Debt Instrument, Covenant, Capacity Threshold, Additional Debt Issuance Cash flows from operating activities: Net Cash Provided by (Used in) Operating Activities [Abstract] Consolidation Consolidation, Policy [Policy Text Block] Ratio of total net indebtedness to consolidated trailing 12-month EBITDA Ratio Of Net Indebtedness To Consolidated Trailing12 Month E B I T D A Ratio of net indebtedness to consolidated trailing 12 month EBITDA. Total current liabilities Liabilities, Current Class of Stock Class of Stock [Domain] Cash paid to acquire investment Payments to Acquire Businesses, Gross Add: Reconciliation Of Net Income To E B I T D A Additions [Abstract] Reconciliation of net Income to EBITDA, additions. Borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Loss Contingencies [Table] Loss Contingencies [Table] Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Common unit - basic (in dollars per share) Net Income (Loss), Per Outstanding Limited Partnership Unit, Basic, Net of Tax Entity Address, Postal Zip Code Entity Address, Postal Zip Code Transfers out Contract with Customer, Asset, Reclassified to Receivable Line of Credit Facility [Line Items] Line of Credit Facility [Line Items] Debt Instrument, Name Debt Instrument, Name [Domain] Title of 12(b) Security Title of 12(b) Security Statement [Table] Statement [Table] Other current assets Other Assets, Current Accrued environmental remediation, beginning balance Accrued environmental remediation, ending balance Accrual for Environmental Loss Contingencies Partners' Capital Partners' Capital [Abstract] New accounting standards recently implemented New Accounting Pronouncements, Policy [Policy Text Block] Statistical Measurement Statistical Measurement [Axis] Subsequent Event Subsequent Event [Member] Cover [Abstract] Cover [Abstract] Intangible assets, net Finite-Lived Intangible Assets, Net Gathering services and related fees Natural Gas, Gathering, Transportation, Marketing and Processing [Member] 2015 Blacktail Release 2015 Blacktail Release [Member] 2015 Blacktail Release Ad valorem taxes payable Increase (Decrease) in Property and Other Taxes Payable Scenario [Domain] Scenario [Domain] Adjustments to reconcile net income (loss) to net cash provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Subsequent Event Type Subsequent Event Type [Axis] Phantom Units Phantom Share Units (PSUs) [Member] Legal fines and other fees Accrual for Environmental Loss Contingencies, Charges to Expense for New Losses Borrowings under Permian Transmission Credit Facility Permian Transmission Credit Facility: Permian Transmission's variable rate senior secured credit facility due March 8, 2028 Permian Transmission Credit Facility [Member] Permian transmission credit facility. Increase in loss contingency accrual Loss Contingency Accrual, Period Increase (Decrease) Deferred Revenue Disclosure [Abstract] Deferred Revenue Disclosure [Abstract] Natural Gas Liquids [Member]