Investment in Unconsolidated Subsidiary (Selected Financial Information) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Schedule of Equity Method Investments [Line Items]
Total Assets	$ 579,955	$ 592,200
Partners' Capital	353,309	357,761
Equity Method Investment, Summarized Financial Information, Income (Loss) from Continuing Operations before Extraordinary Items	(316)	13,756
Equity Method Investment, Summarized Financial Information, Interest and Debt, Expense, Net	(4,156)	(4,426)
Equity Method Investment, Summarized Financial Information, Property, Plant and Equipment, Net	364,598	373,117
Equity Method Investment, Summarized Financial Information, Current Portion of Long Term Debt	60,289	57,514
Equity Method Investment, Summarized Financial Information, Total Long Term Debt	148,242	155,273
Diamond Green Diesel Holdings LLC Joint Venture [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Summarized Financial Information, Current Assets	213,811	216,991
Revenues	116,728	119,657
Net Income	(4,452)	9,348
Equity Method Investment, Summarized Financial Information, Cost of Sales	117,044	105,901
Equity Method Investment, Summarized Financial Information, Other Income	20	18
Equity Method Investment, Summarized Financial Information, Other Assets	1,546	2,092
Equity Method Investment, Summarized Financial Information, Other Current Liabilities	17,765	21,313
Equity Method Investment, Summarized Financial Information, Other Long Term Liabilities	350	339
Equity Method Investment, Summarized Financial Information, Liabilities and Equity	$ 579,955	$ 592,200