Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2021	Apr. 30, 2021
Cover [Abstract]
Entity Registrant Name	Summit Midstream Partners, LP
Entity Central Index Key	0001549922
Document Type	10-Q
Document Period End Date	Mar. 31, 2021
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		6,744,736
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Title of 12(b) Security	Common Units
Trading Symbol	SMLP
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity File Number	001-35666
Entity Tax Identification Number	45-5200503
Entity Address, Address Line One	910 Louisiana Street
Entity Address, Address Line Two	Suite 4200
Entity Address, City or Town	Houston
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	77002
City Area Code	832
Local Phone Number	413-4770
Document Quarterly Report	true
Entity Interactive Data Current	Yes
Document Transition Report	false
Entity Incorporation, State or Country Code	DE