Investment in Unconsolidated Subsidiary (Assets, Liabilities and members' equity) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
ASSETS
Property, plant and equipment, net	$ 360,476	$ 354,871
Total assets	583,617	635,769
Liabilities and members' equity:
Total current portion of long term debt	17,023	17,023
Total long term debt	49,497	53,753
Total liabilities and member's equity	492,570	541,375
Diamond Green Diesel Holdings LLC Joint Venture [Member]
ASSETS
Total current assets	212,915	268,734
Other assets	10,226	12,164
Liabilities and members' equity:
Total other current liabilities	24,100	23,200
Total other long term liabilities	427	418
Equity Method Investment, Summarized Financial Information, Liabilities and Equity	$ 583,617	$ 635,769