Investment in Unconsolidated Subsidiary (Revenues and Expenses) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Expenses:
Operating income	$ 37,642	$ (21,578)	$ 80,637	$ (11,033)
Interest and debt expense, net	(1,406)	(3,122)	(6,148)	(10,629)
Diamond Green Diesel Holdings LLC Joint Venture [Member]
Revenues:
Operating revenues	141,656	107,160	345,650	380,048
Expenses:
Total costs and expenses less depreciation, amortization and accretion expense	96,569	123,779	244,643	376,157
Depreciation, amortization and accretion expense	7,445	4,959	20,370	14,924
Total costs and expenses	104,014	128,738	265,013	391,081
Other income	114	41	199	93
Net income/(loss)	$ 36,350	$ (24,659)	$ 74,688	$ (21,569)