Prepaid Expenses and Other Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Summary of prepaid expense and other assets
Commodity derivatives and related collateral, net	$ 6,136	$ 12,938
Prepaid expenses	23,089	7,901
Deposits	3,949	4,481
RIN inventory	12,657	10,795
Taxes receivable	2,040	2,843
Other	2,502	4,177
Total	$ 50,373	$ 43,135