Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disaggregation of Revenue [Line Items]
Net sales	$ 95,031	$ 86,333	$ 271,239	$ 259,255
Distillery products
Disaggregation of Revenue [Line Items]
Net sales	78,336	72,335	225,365	216,984
Distillery products | Products transferred at a point in time
Disaggregation of Revenue [Line Items]
Net sales	74,999	69,569	216,226	209,024
Distillery products | Services transferred over time
Disaggregation of Revenue [Line Items]
Net sales	3,337	2,766	9,139	7,960
Ingredient solutions
Disaggregation of Revenue [Line Items]
Net sales	16,695	13,998	45,874	42,271
Ingredient solutions | Products transferred at a point in time
Disaggregation of Revenue [Line Items]
Net sales	16,695	13,998	45,874	42,271
Food grade alcohol | Distillery products
Disaggregation of Revenue [Line Items]
Net sales	67,525	63,251	192,435	189,643
Premium beverage alcohol | Distillery products
Disaggregation of Revenue [Line Items]
Net sales	46,864	43,941	133,135	131,868
Industrial alcohol | Distillery products
Disaggregation of Revenue [Line Items]
Net sales	20,661	19,310	59,300	57,775
Fuel grade alcohol | Distillery products
Disaggregation of Revenue [Line Items]
Net sales	1,576	1,458	5,006	4,867
Distillers feed and related co-products | Distillery products
Disaggregation of Revenue [Line Items]
Net sales	5,898	4,860	18,785	14,514
Warehouse services | Distillery products
Disaggregation of Revenue [Line Items]
Net sales	3,337	2,766	9,139	7,960
Specialty wheat starches | Ingredient solutions
Disaggregation of Revenue [Line Items]
Net sales	7,030	7,008	21,170	20,826
Specialty wheat proteins | Ingredient solutions
Disaggregation of Revenue [Line Items]
Net sales	5,486	4,939	16,230	14,541
Commodity wheat starch | Ingredient solutions
Disaggregation of Revenue [Line Items]
Net sales	2,793	1,948	6,926	6,302
Commodity wheat protein | Ingredient solutions
Disaggregation of Revenue [Line Items]
Net sales	$ 1,386	$ 103	$ 1,548	$ 602