Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2016	Jul. 31, 2016
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2016
Document Fiscal Period Focus	Q2
Document Fiscal Year Focus	2016
Entity Registrant Name	SemGroup Corp
Entity Central Index Key	0001489136
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Common Class A [Member]
Entity Common Stock, Shares Outstanding		52,813,816
Class B
Entity Common Stock, Shares Outstanding		0