Investments in Non-Consolidated Subsidiaries - Summarized financial information - NGL Energy (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended			3 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Mar. 31, 2014 NGL Energy Partners LP [Member]	Mar. 31, 2013 NGL Energy Partners LP [Member]	Jun. 30, 2014 NGL Energy Partners LP [Member]	Mar. 31, 2014 NGL Energy Partners LP [Member]	Mar. 31, 2013 NGL Energy Partners LP [Member]	Sep. 30, 2014 Subsequent Event [Member] NGL Energy Partners LP [Member]
Schedule of Equity Method Investments [Line Items]
Gain on issuance of common units by equity method investee	$ 0	$ 0	$ 8,127	$ 0			$ 8,127			$ 18,800
Summarized income statement information
Equity Method Investment, Summarized Financial Information, Revenue					3,975,935	1,617,613		6,719,380	2,955,821
Cost of Goods Sold					3,764,744	1,481,890		6,340,773	2,686,435
Equity Method Investment, Summarized Financial Information, Operating, General and Administrative Expenses					110,923	74,632		201,676	139,325
Equity Method Investment, Summarized Financial Information, Depreciation and Amortization Expense					37,475	27,518		72,969	46,265
Equity Method Investment, Summarized Financial Information, Net Income (Loss)					$ 43,146	$ 22,341		$ 67,198	$ 62,818