Intangible Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Cost	$ 20,181	$ 20,181
Accumulated Amortization	(8,516)	(8,163)
Net	11,665	12,018
Raw material supply agreement
Finite-Lived Intangible Assets [Line Items]
Cost	6,230	6,230
Accumulated Amortization	(3,455)	(3,368)
Net	2,775	2,862
Renewable diesel technology
Finite-Lived Intangible Assets [Line Items]
Cost	8,300	8,300
Accumulated Amortization	(3,228)	(3,089)
Net	5,072	5,211
Acquired customer relationships
Finite-Lived Intangible Assets [Line Items]
Cost	4,747	4,747
Accumulated Amortization	(1,658)	(1,535)
Net	3,089	3,212
Trademarks
Finite-Lived Intangible Assets [Line Items]
Cost	904	904
Accumulated Amortization	(175)	(171)
Net	$ 729	$ 733