Summary of Significant Accounting Policies - (Details Textual)	1 Months Ended		3 Months Ended								7 Months Ended	12 Months Ended			21 Months Ended	24 Months Ended
	Jun. 30, 2017 USD ($) a	Jun. 30, 2016 shares	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($) a	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2017 USD ($) renewable_identification_number shares	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($) customer	Dec. 31, 2016 USD ($)	Dec. 31, 2017 USD ($)	Jun. 02, 2016 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Biomass-based diesel government incentives												$ 28,728,000	$ 346,672,000	$ 245,868,000
Accounts receivable, net			$ 90,648,000				$ 164,949,000				$ 90,648,000	90,648,000	164,949,000		$ 164,949,000	$ 90,648,000
Estimated impaired fixed assets											2,671,000
Insurance recoveries			5,000,000	$ 3,000,000								8,000,000			19,037,000
Proceeds from business interruption insurance												2,000,000
Adjacent land purchased | a	61				61
Payments for land acquisition	$ 20,000,000
Lease termination loss					$ (3,967,000)
Capitalization of interest incurred on debt during construction			301,000				537,000				301,000	301,000	537,000	897,000	537,000	301,000
Impairment of goodwill												0	0	175,028,000
Impairment of property, plant and equipment, net			48,532,000	$ 0	1,341,000	$ 0	17,893,000	$ 0	$ 0	$ 0		49,873,000	17,893,000	0
Impairment charges due to deteriorating physical condition												5,224,000	2,300,000
Fair value of embedded conversion option												27,908,000
Tax impact of 2036 Senior Notes conversion liability reclassification												18,025,000
Change in fair value of convertible debt conversion liability												$ (18,833,000)	13,045,000	0
Shares covered by rebalancing call options												100.00%
Revenues associated with government incentive programs												$ 607,000	434,000	624,000
Advertising and promotional expenses												2,140,000	1,746,000	1,288,000
Impairment of IPR&D												$ 0	0	0
Matching contributions												50.00%
Participants eligible earnings												6.00%
Total expense related to the Company's defined contribution plan												$ 1,367,000	1,168,000	$ 1,071,000
Cash, coverage by U.S. FDIC			250,000								250,000	$ 250,000				250,000
Share repurchase program, shares repurchased (in shares) | shares												0
Customer A
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of customers | customer														1
March 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock repurchase program, amount authorized to be repurchased			75,000,000								75,000,000	$ 75,000,000				75,000,000
Convertible Senior Notes | 2036 Convertible Notes
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Face amount	$ 152,000,000				$ 152,000,000												$ 152,000,000
Interest rate	4.00%				4.00%												4.00%
Fair value of embedded conversion option												45,933,000
Tax impact of 2036 Senior Notes conversion liability reclassification												$ 18,025,000
Share repurchase program, shares repurchased (in shares) | shares		4,060,323
Services
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Minimum percentage increase in fair value of each of the reporting units over its carrying value through annual impairment test												49.00%
New Orleans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Impairment of property, plant and equipment, net			44,649,000									$ 44,649,000
Emporia
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Impairment of property, plant and equipment, net													15,593,000
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RINs per gallon | renewable_identification_number												1.5
Allowed RINs per gallon | renewable_identification_number												0
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RINs per gallon | renewable_identification_number												1.7
Allowed RINs per gallon | renewable_identification_number												2.5
In-process research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Useful life												15 years
Biodiesel Mixture Excise Tax Credit
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Biomass-based diesel government incentives																86,504,000
Accounts receivable, net			$ 2,762,000				$ 89,266,000				$ 2,762,000	$ 2,762,000	$ 89,266,000		$ 89,266,000	$ 2,762,000