Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Disaggregation of Revenue [Line Items]
Net sales	$ 87,956	$ 87,169
Distillery products
Disaggregation of Revenue [Line Items]
Net sales	74,377	73,950
Distillery products | Products transferred at a point in time
Disaggregation of Revenue [Line Items]
Net sales	71,502	71,327
Distillery products | Services transferred over time
Disaggregation of Revenue [Line Items]
Net sales	2,875	2,623
Ingredient solutions
Disaggregation of Revenue [Line Items]
Net sales	13,579	13,219
Food grade alcohol | Distillery products
Disaggregation of Revenue [Line Items]
Net sales	63,415	64,763
Premium beverage alcohol | Distillery products
Disaggregation of Revenue [Line Items]
Net sales	44,071	45,640
Industrial alcohol | Distillery products
Disaggregation of Revenue [Line Items]
Net sales	19,344	19,123
Fuel grade alcohol | Distillery products
Disaggregation of Revenue [Line Items]
Net sales	1,863	1,642
Distillers feed and related co-products | Distillery products
Disaggregation of Revenue [Line Items]
Net sales	6,224	4,922
Specialty wheat starches | Ingredient solutions
Disaggregation of Revenue [Line Items]
Net sales	6,801	6,407
Specialty wheat proteins | Ingredient solutions
Disaggregation of Revenue [Line Items]
Net sales	4,736	4,378
Commodity wheat starch | Ingredient solutions
Disaggregation of Revenue [Line Items]
Net sales	2,042	2,088
Commodity wheat protein | Ingredient solutions
Disaggregation of Revenue [Line Items]
Net sales	$ 0	$ 346