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Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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Percentage investment held by the managing member or general partner of the limited liability company (LLC) or limited partnership (LP).

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The number of limited partner units outstanding.

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The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

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The number of units or percentage investment held in the subsidiary by the limited liability company or limited partnership.

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Percentage of subsidiary's or equity method investee's stock owned by parent immediately after all stock transactions.

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ORGANIZATION, BUSINESS OPERATIONS AND PRESENTATION AND CONSOLIDATION - Narrative (Details) - USD ($) $ in Millions	1 Months Ended			12 Months Ended
	Sep. 30, 2016	Feb. 29, 2016	Mar. 31, 2014	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Organization And Business Operations [Line Items]
Common limited partner capital (in shares)				72,111,000		42,063,000
Other noncurrent assets \| Accounting Standards Update 2015-03
Organization And Business Operations [Line Items]
Deferred loan costs						$ 9.2
Long-term debt \| Accounting Standards Update 2015-03
Organization And Business Operations [Line Items]
Deferred loan costs						$ (9.2)
Summit Holdings
Organization And Business Operations [Line Items]
Cumulative percentage ownership in subsidiary				100.00%
Summit Holdings \| DFW Midstream
Organization And Business Operations [Line Items]
Cumulative percentage ownership in subsidiary				100.00%
SMP Holdings \| Contributed Entities
Organization And Business Operations [Line Items]
Join venture interest		100.00%
SMP Holdings \| OGC
Organization And Business Operations [Line Items]
Percentage of ownership interest		40.00%
Drop Down Assets 2016 Acquisition
Organization And Business Operations [Line Items]
Ownership percentage by noncontrolling owners				1.00%	1.00%
Common units \| Summit Investments
Organization And Business Operations [Line Items]
Common limited partner capital (in shares)				29,854,581
General Partner
Organization And Business Operations [Line Items]
General partner interest	2.00%		2.00%	2.00%
General Partner \| Summit Investments \| Summit Midstream Partners, LP
Organization And Business Operations [Line Items]
General partner interest				2.00%