CONDENSED CONSOLIDATING FINANCIAL INFORMATION - Condensed Cash Flow Statement (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities:
Net cash (used in) provided by operating activities	$ 51,210	$ 62,449
Cash flows from investing activities:
Capital expenditures	(40,778)	(14,428)
Contributions to equity method investees	0	(4,936)
Other, net	(221)	(361)
Advances to affiliates	0	0
Net cash provided by (used in) investing activities	(40,999)	(19,725)
Cash flows from financing activities:
Distributions to unitholders	(45,053)	(44,452)
Borrowings under Revolving Credit Facility	50,000	72,000
Repayments under Revolving Credit Facility	(10,000)	(245,000)
Debt issuance costs	(4)	(6,825)
Payment of redemption and call premiums on senior notes	0	(17,913)
Proceeds from ATM Program common unit issuances, net of costs	0	367
Contribution from General Partner	0	113
Issuance of senior notes	0	500,000
Tender and redemption of senior notes	0	(300,000)
Other, net	(3,218)	(2,157)
Advances from affiliates	0	0
Net cash provided by (used in) financing activities	(8,275)	(43,867)
Net change in cash and cash equivalents	1,936	(1,143)
Cash and cash equivalents, beginning of period	1,430	7,428
Cash and cash equivalents, end of period	3,366	6,285
Consolidating adjustments
Cash flows from operating activities:
Net cash (used in) provided by operating activities	0	0
Cash flows from investing activities:
Capital expenditures	0	0
Contributions to equity method investees		0
Other, net	0	0
Advances to affiliates	51,262	92,260
Net cash provided by (used in) investing activities	51,262	92,260
Cash flows from financing activities:
Distributions to unitholders	0	0
Borrowings under Revolving Credit Facility	0	0
Repayments under Revolving Credit Facility	0	0
Debt issuance costs	0	0
Payment of redemption and call premiums on senior notes		0
Proceeds from ATM Program common unit issuances, net of costs		0
Contribution from General Partner		0
Issuance of senior notes		0
Tender and redemption of senior notes		0
Other, net	0	0
Advances from affiliates	(51,262)	(92,260)
Net cash provided by (used in) financing activities	(51,262)	(92,260)
Net change in cash and cash equivalents	0	0
Cash and cash equivalents, beginning of period	0	0
Cash and cash equivalents, end of period	0	0
Summit Midstream Partners, LP | Reportable Legal Entities
Cash flows from operating activities:
Net cash (used in) provided by operating activities	(2,721)	(2,021)
Cash flows from investing activities:
Capital expenditures	(297)	(1,003)
Contributions to equity method investees		0
Other, net	(221)	(361)
Advances to affiliates	0	(20,185)
Net cash provided by (used in) investing activities	(518)	(21,549)
Cash flows from financing activities:
Distributions to unitholders	(45,053)	(44,452)
Borrowings under Revolving Credit Facility	0	0
Repayments under Revolving Credit Facility	0	0
Debt issuance costs	0	0
Payment of redemption and call premiums on senior notes		0
Proceeds from ATM Program common unit issuances, net of costs		367
Contribution from General Partner		113
Issuance of senior notes		0
Tender and redemption of senior notes		0
Other, net	(2,883)	(2,051)
Advances from affiliates	51,262	72,075
Net cash provided by (used in) financing activities	3,326	26,052
Net change in cash and cash equivalents	87	2,482
Cash and cash equivalents, beginning of period	126	698
Cash and cash equivalents, end of period	213	3,180
Co-Issuers | Reportable Legal Entities
Cash flows from operating activities:
Net cash (used in) provided by operating activities	(10,985)	(27,574)
Cash flows from investing activities:
Capital expenditures	0	0
Contributions to equity method investees		0
Other, net	0	0
Advances to affiliates	(28,718)	0
Net cash provided by (used in) investing activities	(28,718)	0
Cash flows from financing activities:
Distributions to unitholders	0	0
Borrowings under Revolving Credit Facility	50,000	72,000
Repayments under Revolving Credit Facility	(10,000)	(245,000)
Debt issuance costs	(4)	(6,825)
Payment of redemption and call premiums on senior notes		(17,913)
Proceeds from ATM Program common unit issuances, net of costs		0
Contribution from General Partner		0
Issuance of senior notes		500,000
Tender and redemption of senior notes		(300,000)
Other, net	0	0
Advances from affiliates	0	25,266
Net cash provided by (used in) financing activities	39,996	27,528
Net change in cash and cash equivalents	293	(46)
Cash and cash equivalents, beginning of period	75	51
Cash and cash equivalents, end of period	368	5
Guarantor Subsidiaries | Reportable Legal Entities
Cash flows from operating activities:
Net cash (used in) provided by operating activities	47,495	75,271
Cash flows from investing activities:
Capital expenditures	(39,001)	(6,089)
Contributions to equity method investees		0
Other, net	0	0
Advances to affiliates	(6,995)	(72,075)
Net cash provided by (used in) investing activities	(45,996)	(78,164)
Cash flows from financing activities:
Distributions to unitholders	0	0
Borrowings under Revolving Credit Facility	0	0
Repayments under Revolving Credit Facility	0	0
Debt issuance costs	0	0
Payment of redemption and call premiums on senior notes		0
Proceeds from ATM Program common unit issuances, net of costs		0
Contribution from General Partner		0
Issuance of senior notes		0
Tender and redemption of senior notes		0
Other, net	(306)	(91)
Advances from affiliates	0	0
Net cash provided by (used in) financing activities	(306)	(91)
Net change in cash and cash equivalents	1,193	(2,984)
Cash and cash equivalents, beginning of period	1,138	5,768
Cash and cash equivalents, end of period	2,331	2,784
Non-Guarantor Subsidiaries | Reportable Legal Entities
Cash flows from operating activities:
Net cash (used in) provided by operating activities	17,421	16,773
Cash flows from investing activities:
Capital expenditures	(1,480)	(7,336)
Contributions to equity method investees		(4,936)
Other, net	0	0
Advances to affiliates	(15,549)	0
Net cash provided by (used in) investing activities	(17,029)	(12,272)
Cash flows from financing activities:
Distributions to unitholders	0	0
Borrowings under Revolving Credit Facility	0	0
Repayments under Revolving Credit Facility	0	0
Debt issuance costs	0	0
Payment of redemption and call premiums on senior notes		0
Proceeds from ATM Program common unit issuances, net of costs		0
Contribution from General Partner		0
Issuance of senior notes		0
Tender and redemption of senior notes		0
Other, net	(29)	(15)
Advances from affiliates	0	(5,081)
Net cash provided by (used in) financing activities	(29)	(5,096)
Net change in cash and cash equivalents	363	(595)
Cash and cash equivalents, beginning of period	91	911
Cash and cash equivalents, end of period	$ 454	$ 316