Acquisitions - Pro Forma (Details) - Imperium Renewables, Inc. - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Business Acquisition [Line Items]
Revenues	$ 1,505,513	$ 1,453,331	$ 1,556,798
Net income (loss)	$ (155,870)	$ 94,129	$ 172,314
Basic net income (loss) per share (in dollars per share)	$ (3.46)	$ 2.22	$ 4.96