Document and Entity Information	6 Months Ended
	Jun. 30, 2013	Jul. 31, 2013 Class A	Jul. 31, 2013 Class B
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2013
Document Fiscal Period Focus	Q2
Document Fiscal Year Focus	2013
Entity Registrant Name	SemGroup Corp
Entity Central Index Key	0001489136
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		42,021,494	28,235