Other Assets - (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Summary of prepaid expense and other current assets
Commodity derivatives and related collateral, net	$ 1,610	$ 7,127
Prepaid expenses	11,733	10,665
Deposits	2,899	2,897
RIN inventory	27,028	9,398
Taxes receivable	6,356	4,539
Other	2,254	1,646
Total	$ 51,880	$ 36,272