ORGANIZATION, BUSINESS OPERATIONS AND PRESENTATION AND CONSOLIDATION	9 Months Ended
Sep. 30, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
ORGANIZATION, BUSINESS OPERATIONS AND PRESENTATION AND CONSOLIDATION	1. ORGANIZATION, BUSINESS OPERATIONS AND PRESENTATION AND CONSOLIDATION Organization. SMLP, a Delaware limited partnership, 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. Our business activities are conducted through various operating subsidiaries, each of which is owned or controlled by our wholly owned subsidiary holding company, Summit Holdings, a Delaware limited liability company. References to the "Partnership," "we," or "our" refer collectively to SMLP and its subsidiaries. On May 28, 2020, the Partnership closed the transactions contemplated by the Purchase Agreement (the “Purchase Agreement”), dated May 3, 2020, with affiliates of its then private equity sponsor, Energy Capital Partners II, LLC (“ECP”), to acquire Summit Midstream Partners, LLC (“Summit Investments”). The purchase of Summit Investments resulted in the Partnership acquiring an indirect ownership interest in Summit Midstream Partners Holdings, LLC, a Delaware limited liability company (“SMP Holdings”), which in turn owned (a) 34,604,581 SMLP common units representing limited partner interests in the Partnership (the “common units”) that were pledged as collateral under the SMPH Term Loan, (b) 10,714,285 SMLP common units that were not pledged as collateral under the SMPH Term Loan and (c) a deferred purchase price obligation receivable owed by the Partnership. In addition, the Partnership acquired 5,915,827 SMLP common units held by an affiliate of ECP. The total purchase price was $35.0 million in cash and warrants to purchase up to 10 million SMLP common units (refer to Note 11 – Partners’ Capital and Mezzanine Capital for additional details). Pursuant to the Purchase Agreement, the Partnership, through its indirect ownership interest of SMP Holdings, will retain any liabilities stemming from the release of produced water from a produced water pipeline operated by Meadowlark Midstream Company, LLC, a subsidiary of the Partnership, that occurred near Williston, North Dakota and was discovered on January 6, 2015. These transactions are collectively referred to as the “GP Buy-In Transaction.” As a result of the GP Buy-In Transaction, the Partnership indirectly owns its General Partner. Following the closing of the GP Buy-In Transaction, the Partnership retired 16,630,112 SMLP common units it acquired that are not pledged as collateral under the SMPH Term Loan. The 34,604,581 SMLP common units that are pledged as collateral under the SMPH Term Loan are not considered outstanding with respect to voting and distributions under the Partnership Agreement so long as they are held by a subsidiary of the Partnership. Under GAAP, the GP Buy-In Transaction was deemed a transaction among entities under common control with a change in reporting entity. Although SMLP is the surviving entity for legal purposes, Summit Investments is the surviving entity for accounting purposes; therefore, the historical financial results included herein, prior to the GP Buy-In Transaction are those of Summit Investments. Prior to the GP Buy-In Transaction, Summit Investments controlled SMLP and SMLP’s financial statements were consolidated into Summit Investments. 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. 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. Presentation and Consolidation. The condensed consolidated financial statements contained in this report include all normal and recurring material adjustments that, in the opinion of management, are necessary for a fair statement of the financial position, results of operations and cash flows for the interim periods presented herein. The accompanying condensed consolidated financial statements were prepared using GAAP for interim financial information and in accordance with the rules and regulations of the Securities and Exchange Commission. As permitted under those rules, certain information relating to the Partnership’s organization and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been appropriately condensed or omitted. Therefore, these condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and the notes thereto included in the Partnership’s Annual Report for the year ended December 31, 2019 (“2019 Annual Report”). The Partnership believes the disclosures made are adequate to make the information presented not misleading. Risks and Uncertainties. The Partnership is closely monitoring the impact of the outbreak of COVID-19 on all aspects of its business, including how it has impacted and will impact its customers, employees, supply chain and distribution network. While COVID-19 did not have a material adverse effect on the Partnership’s reported results for the first nine months of 2020, the Partnership is unable to predict the ultimate impact that COVID-19 may have on its business, future results of operations, financial position or cash flows. Given the dynamic nature of the COVID-19 pandemic and related market conditions, the Partnership cannot reasonably estimate the period of time that these events will persist or the full extent of the impact they will have on its business. The full extent to which the Partnership’s operations may be impacted by the COVID-19 pandemic will depend largely on future developments, which are highly uncertain and cannot be accurately predicted, including changes in the severity of the pandemic, countermeasures taken by governments, businesses and individuals to slow the spread of the pandemic, and the ability of pharmaceutical companies to develop effective and safe vaccines and therapeutic drugs. Furthermore, the impacts of a potential worsening of global economic conditions and the continued disruptions to and volatility in the financial markets remain unknown.

ORGANIZATION, BUSINESS OPERATIONS AND PRESENTATION AND CONSOLIDATION

9 Months Ended

Sep. 30, 2020

Organization Consolidation And Presentation Of Financial Statements [Abstract]

ORGANIZATION, BUSINESS OPERATIONS AND PRESENTATION AND CONSOLIDATION

1. ORGANIZATION, BUSINESS OPERATIONS AND PRESENTATION AND CONSOLIDATION

Organization. SMLP, a Delaware limited partnership, 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. Our business activities are conducted through various operating subsidiaries, each of which is owned or controlled by our wholly owned subsidiary holding company, Summit Holdings, a Delaware limited liability company. References to the "Partnership," "we," or "our" refer collectively to SMLP and its subsidiaries.

On May 28, 2020, the Partnership closed the transactions contemplated by the Purchase Agreement (the “Purchase Agreement”), dated May 3, 2020, with affiliates of its then private equity sponsor, Energy Capital Partners II, LLC (“ECP”), to acquire Summit Midstream Partners, LLC (“Summit Investments”). The purchase of Summit Investments resulted in the Partnership acquiring an indirect ownership interest in Summit Midstream Partners Holdings, LLC, a Delaware limited liability company (“SMP Holdings”), which in turn owned (a) 34,604,581 SMLP common units representing limited partner interests in the Partnership (the “common units”) that were pledged as collateral under the SMPH Term Loan, (b) 10,714,285 SMLP common units that were not pledged as collateral under the SMPH Term Loan and (c) a deferred purchase price obligation receivable owed by the Partnership. In addition, the Partnership acquired 5,915,827 SMLP common units held by an affiliate of ECP. The total purchase price was $35.0 million in cash and warrants to purchase up to 10 million SMLP common units (refer to Note 11 – Partners’ Capital and Mezzanine Capital for additional details). Pursuant to the Purchase Agreement, the Partnership, through its indirect ownership interest of SMP Holdings, will retain any liabilities stemming from the release of produced water from a produced water pipeline operated by Meadowlark Midstream Company, LLC, a subsidiary of the Partnership, that occurred near Williston, North Dakota and was discovered on January 6, 2015. These transactions are collectively referred to as the “GP Buy-In Transaction.”

As a result of the GP Buy-In Transaction, the Partnership indirectly owns its General Partner. Following the closing of the GP Buy-In Transaction, the Partnership retired 16,630,112 SMLP common units it acquired that are not pledged as collateral under the SMPH Term Loan. The 34,604,581 SMLP common units that are pledged as collateral under the SMPH Term Loan are not considered outstanding with respect to voting and distributions under the Partnership Agreement so long as they are held by a subsidiary of the Partnership.

Under GAAP, the GP Buy-In Transaction was deemed a transaction among entities under common control with a change in reporting entity. Although SMLP is the surviving entity for legal purposes, Summit Investments is the surviving entity for accounting purposes; therefore, the historical financial results included herein, prior to the GP Buy-In Transaction are those of Summit Investments. Prior to the GP Buy-In Transaction, Summit Investments controlled SMLP and SMLP’s financial statements were consolidated into Summit Investments.

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. 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.

Presentation and Consolidation. The condensed consolidated financial statements contained in this report include all normal and recurring material adjustments that, in the opinion of management, are necessary for a fair statement of the financial position, results of operations and cash flows for the interim periods presented herein.

The accompanying condensed consolidated financial statements were prepared using GAAP for interim financial information and in accordance with the rules and regulations of the Securities and Exchange Commission. As permitted under those rules, certain information relating to the Partnership’s organization and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been appropriately condensed or omitted. Therefore, these condensed consolidated financial statements should be read in conjunction with the

consolidated financial statements and the notes thereto included in the Partnership’s Annual Report for the year ended December 31, 2019 (“2019 Annual Report”). The Partnership believes the disclosures made are adequate to make the information presented not misleading.

Risks and Uncertainties. The Partnership is closely monitoring the impact of the outbreak of COVID-19 on all aspects of its business, including how it has impacted and will impact its customers, employees, supply chain and distribution network. While COVID-19 did not have a material adverse effect on the Partnership’s reported results for the first nine months of 2020, the Partnership is unable to predict the ultimate impact that COVID-19 may have on its business, future results of operations, financial position or cash flows.

Given the dynamic nature of the COVID-19 pandemic and related market conditions, the Partnership cannot reasonably estimate the period of time that these events will persist or the full extent of the impact they will have on its business. The full extent to which the Partnership’s operations may be impacted by the COVID-19 pandemic will depend largely on future developments, which are highly uncertain and cannot be accurately predicted, including changes in the severity of the pandemic, countermeasures taken by governments, businesses and individuals to slow the spread of the pandemic, and the ability of pharmaceutical companies to develop effective and safe vaccines and therapeutic drugs. Furthermore, the impacts of a potential worsening of global economic conditions and the continued disruptions to and volatility in the financial markets remain unknown.