Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Sales (Note 2)	$ 90,501	$ 88,252	$ 179,597	$ 176,208
Distillery products
Disaggregation of Revenue [Line Items]
Sales (Note 2)	74,023	72,652	148,600	147,029
Ingredient solutions
Disaggregation of Revenue [Line Items]
Sales (Note 2)	16,478	15,600	30,997	29,179
Premium beverage alcohol | Distillery products
Disaggregation of Revenue [Line Items]
Sales (Note 2)	42,312	42,200	84,321	86,271
Brown goods | Distillery products
Disaggregation of Revenue [Line Items]
Sales (Note 2)	27,621	27,736	52,448	55,937
White goods | Distillery products
Disaggregation of Revenue [Line Items]
Sales (Note 2)	14,691	14,464	31,873	30,334
Industrial alcohol | Distillery products
Disaggregation of Revenue [Line Items]
Sales (Note 2)	20,636	19,295	41,079	38,639
Food grade alcohol | Distillery products
Disaggregation of Revenue [Line Items]
Sales (Note 2)	62,948	61,495	125,400	124,910
Fuel grade alcohol | Distillery products
Disaggregation of Revenue [Line Items]
Sales (Note 2)	1,398	1,567	2,899	3,430
Distillers feed and related co-products | Distillery products
Disaggregation of Revenue [Line Items]
Sales (Note 2)	6,181	6,663	13,276	12,887
Warehouse services | Distillery products
Disaggregation of Revenue [Line Items]
Sales (Note 2)	3,496	2,927	7,025	5,802
Specialty wheat starches | Ingredient solutions
Disaggregation of Revenue [Line Items]
Sales (Note 2)	7,210	7,339	14,090	14,140
Specialty wheat proteins | Ingredient solutions
Disaggregation of Revenue [Line Items]
Sales (Note 2)	5,276	6,008	9,718	10,744
Commodity wheat starches | Ingredient solutions
Disaggregation of Revenue [Line Items]
Sales (Note 2)	3,013	2,090	5,275	4,132
Commodity wheat proteins | Ingredient solutions
Disaggregation of Revenue [Line Items]
Sales (Note 2)	$ 979	$ 163	$ 1,914	$ 163