Related Party Transactions - Summary of Related Party Transactions - Consolidated Statements of Operations (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Summary of Related Party Transactions
Cost of goods sold - Biodiesel	[1]	$ 4,542	$ 42,622	$ 49,358
Selling, general, and administrative expenses	[1]	0	45	37
Interest expense	[1]	$ 0	$ 7	$ 30

[1] Represents transactions with West Central prior to the Company's determination that West Central was no longer a related party.