Supplemental Cash Flow Information Supplemental Cash Flow Information (Details Textual) (USD $)	9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012	Dec. 31, 2012
Sale of interest in equity investment to related party	$ 33,716,000	[1]
Tax effect of adjustment to APIC from sale of equity investment to less than wholly owned subsidiary	33,700,000
Warrants exercised during period	772,817
Proceeds from warrant exercises	225,000		0
Interest Paid	7,300,000		4,400,000
Income Taxes Paid, Net	6,600,000		5,500,000
Capital Expenditures Incurred but Not yet Paid	16,400,000		7,000,000
Accrued liabilities	81,509,000			63,831,000
Noncontrolling Interest [Member]
Sale of interest in equity investment to related party	90,516,000	[1]
Additional Paid-in Capital [Member]
Sale of interest in equity investment to related party	(56,800,000)	[1]
Warrant [Member]
Stock Issued During Period, Shares, Conversion of Convertible Securities	425,618
Adjustments to Additional Paid in Capital, Other	23,500,000
Semcrude Pipeline [Member]
Equity Method Investment, Ownership Percentage	33.00%
Goodwill related to unpaid invoices representing purchase price adjustments [Member]
Accrued liabilities	$ 9,000,000

[1] * On January 13, 2013, we contributed a 33% interest in SemCrude Pipeline, L.L.C. to our consolidated subsidiary, Rose Rock. As this transaction was between entities under common control, the interest in SemCrude Pipeline, L.L.C. was recorded by Rose Rock based on SemGroup's book value. This amount represents the purchase price in excess of book value which was attributed to the noncontrolling interest owners of Rose Rock. The entry to additional paid-in capital has been recorded net of tax.