Other Assets (Tables)

12 Months Ended

Dec. 31, 2017

Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]

Summary of prepaid expense and other current assets

Prepaid expenses and other current assets consist of the following at December 31:

	2017		2016
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

Summary of other noncurrent assets

Other noncurrent assets consist of the following at December 31:

	2017		2016
Spare parts inventory	$	2,764	$	3,532
Catalysts	2,962		4,479
Deposits	381		2,392
Other	933		2,227
Total	$	7,040	$	12,630