Acquisitions and Equity Transactions (Details Textual) $ in Thousands, gal in Millions			3 Months Ended	9 Months Ended
	Aug. 19, 2015 USD ($) shares gal	Dec. 24, 2014 USD ($) shares	Dec. 31, 2014 USD ($)	Sep. 30, 2015 USD ($) gal	Sep. 30, 2014 USD ($)
Business Acquisition [Line Items]
Production capacity per year | gal				432
Contingent consideration for acquisitions			$ 30,091	$ 34,059
Bargain purchase gain				5,358	$ 0
Goodwill			188,275	$ 191,477
Imperium Renewables, Inc.
Business Acquisition [Line Items]
Production capacity per year | gal	100			100
Shares of common stock issued | shares	1,675,000
Contingent consideration for acquisitions	$ 5,000			$ 5,000
Earnout payment period	2 years
Current contingent liability				2,167
Bargain purchase gain				$ 5,358
Cash	$ 36,748
Fair value of noncontrolling interest	$ 57,058
Petrotec AG
Business Acquisition [Line Items]
Shares of common stock issued | shares		2,070,538
Equity interest		69.08%		85.93%
Cash				$ 4,416
Goodwill		$ 369
Noncontrolling interest percent		30.92%
Fair value of noncontrolling interest		$ 8,962
Acquisition related costs			$ 1,289