Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Oct. 31, 2018
Entity Information [Line Items]
Entity Registrant Name	Summit Midstream Partners, LP
Entity Central Index Key	0001549922
Document Type	10-Q
Document Period End Date	Sep. 30, 2018
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q3
Trading Symbol	SMLP
Common units
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		73,356,950
General Partner Units
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		1,490,999