Long-Term Debt (Details Textual)	3 Months Ended										3 Months Ended								3 Months Ended									3 Months Ended					0 Months Ended	3 Months Ended				1 Months Ended
	Mar. 31, 2013 USD ($)	Mar. 31, 2012 USD ($)	Mar. 31, 2013 SemGroup Corporate Revolving Credit Facility [Member] USD ($)	Mar. 31, 2013 SemGroup Corporate Revolving Credit Facility [Member] Alternate Base Rate Borrowings [Member]	Mar. 31, 2013 Rose Rock Credit Facility [Member] USD ($)	Mar. 31, 2012 Rose Rock Credit Facility [Member] USD ($)	Mar. 31, 2013 Rose Rock Credit Facility [Member] Bilateral Letter of Credit [Member] USD ($)	Mar. 31, 2013 Rose Rock Credit Facility [Member] Letter of Credit [Member] USD ($)	Mar. 31, 2013 Rose Rock Credit Facility [Member] Eurodollar Rate Borrowings [Member]	Mar. 31, 2013 Rose Rock Credit Facility [Member] Alternate Base Rate Borrowings [Member]	Mar. 31, 2013 Rose Rock Credit Facility [Member] Minimum [Member]	Mar. 31, 2013 Rose Rock Credit Facility [Member] Maximum [Member]	Mar. 31, 2013 SemMexico Credit Facility [Member] USD ($)	Mar. 31, 2012 SemMexico Credit Facility [Member] USD ($)	Mar. 31, 2013 Letter of Credit [Member] SemGroup Corporate Revolving Credit Facility [Member] USD ($)	Mar. 31, 2013 Letter of Credit [Member] SemGroup Corporate Revolving Credit Facility [Member] Maximum [Member] USD ($)	Mar. 31, 2013 Letter of Credit [Member] SemMexico Credit Facility [Member] USD ($)	Mar. 31, 2013 Letter of Credit [Member] SemMexico Credit Facility [Member] MXN	Mar. 31, 2013 Revolving Credit Facility [Member] SemGroup Corporate Revolving Credit Facility [Member] USD ($)	Mar. 31, 2012 Revolving Credit Facility [Member] SemGroup Corporate Revolving Credit Facility [Member] USD ($)	Apr. 22, 2013 Revolving Credit Facility [Member] SemGroup Corporate Revolving Credit Facility [Member] USD ($)	Mar. 31, 2013 Revolving Credit Facility [Member] SemGroup Corporate Revolving Credit Facility [Member] Alternate Base Rate Borrowings [Member] USD ($)	Mar. 31, 2013 Revolving Credit Facility [Member] SemGroup Corporate Revolving Credit Facility [Member] Maximum [Member] USD ($)	Mar. 31, 2013 Revolving Credit Facility [Member] Rose Rock Credit Facility [Member] Eurodollar Rate Borrowings [Member] USD ($)	Mar. 31, 2013 Revolving Credit Facility [Member] Rose Rock Credit Facility [Member] Alternate Base Rate Borrowings [Member] USD ($)	Mar. 31, 2013 Revolving Credit Facility [Member] SemMexico Credit Facility [Member] USD ($)	Mar. 31, 2013 Revolving Credit Facility [Member] SemMexico Credit Facility [Member] MXN	Mar. 31, 2013 Revolving Credit Agreements [Member] SemMexico Credit Facility [Member] USD ($)	Mar. 31, 2013 Revolving Credit Agreements [Member] SemMexico Credit Facility [Member] Additional Credit Agreement [Member] USD ($)	Mar. 31, 2013 Revolving Credit Agreements [Member] SemMexico Credit Facility [Member] Additional Credit Agreement [Member] MXN	Mar. 31, 2013 1.75% Letter of Credit [Member] Rose Rock Credit Facility [Member] Bilateral Letter of Credit [Member] USD ($)	Mar. 31, 2013 2.0% Letter of Credit [Member] Rose Rock Credit Facility [Member] Bilateral Letter of Credit [Member] USD ($)	Jan. 13, 2013 Rose Rock Midstream, L.P. [Member] USD ($)	Mar. 31, 2013 Rose Rock Midstream, L.P. [Member] USD ($)	Mar. 31, 2013 Rose Rock Midstream, L.P. [Member] Revolving Credit Facility [Member] USD ($)	Jan. 13, 2013 Rose Rock Midstream, L.P. [Member] Revolving Credit Facility [Member] USD ($)	Dec. 31, 2012 Rose Rock Midstream, L.P. [Member] Revolving Credit Facility [Member] Rose Rock Credit Facility [Member] USD ($)	May 31, 2013 Subsequent Event [Member] Revolving Credit Facility [Member] SemGroup Corporate Revolving Credit Facility [Member] USD ($)	May 03, 2013 Subsequent Event [Member] Revolving Credit Facility [Member] SemGroup Corporate Revolving Credit Facility [Member] USD ($)	May 03, 2013 Subsequent Event [Member] Revolving Credit Facility [Member] SemGroup Corporate Revolving Credit Facility [Member] Maximum [Member] USD ($)
Long Term Debt (Textual) [Abstract]
Capacity of revolving credit facility																																				$ 385,000,000	$ 150,000,000
Proceeds from Lines of Credit																																	133,500,000
Borrowings outstanding																						23,500,000		100,000,000	52,500,000			0	4,500,000	56,000,000
Letters of credit outstanding							6,100,000	48,900,000							5,100,000		23,700,000	292,800,000													1,100,000	5,000,000
Prime rate used to determine interest rate				3.25%
Interest rate in effect																															1.75%	2.00%
Debt instrument, applicable margin percentage				1.50%
Fees charged on outstanding letters of credit effect rate			2.50%		2.75%								0.50%
Percentage of line of credit facility fronting fee			0.25%		0.25%
Commitment fee on unused capacity			0.50%								0.375%	0.50%
Unamortized debt costs			3,200,000		2,900,000
Maximum borrowing capacity																250,000,000							300,000,000			3,600,000	44,000,000		4,500,000	56,000,000									500,000,000
Margin added to Prime Rate to determine effective interest rate																												2.00%	1.70%	1.70%
Interest expense recorded					2,000,000	500,000							7,000	100,000					1,200,000	1,500,000
Line of Credit Facility, Maximum Borrowing Incremental Increases																					300,000,000														165,000,000					100,000,000
Senior Unsecured Indebtedness Threshold																					200,000,000
Line of Credit Facility, Incremental Increase																																							200,000,000
Effective interest rate			4.75%						3.04%	5.00%																			6.03%	6.03%
Debt Issuance Cost																																		1,600,000				2,200,000
Interest Costs Capitalized	$ 900,000	$ 100,000