Revenue (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disaggregation of Revenue [Line Items]
Net sales	$ 104,850	$ 95,031	$ 88,252	$ 87,956	$ 88,193	$ 86,333	$ 85,753	$ 87,169	$ 376,089	$ 347,448	$ 318,263
Distillery products
Disaggregation of Revenue [Line Items]
Net sales									314,055	291,008	265,243
Distillery products | Products transferred at a point in time
Disaggregation of Revenue [Line Items]
Net sales									301,126	280,334	256,806
Distillery products | Services transferred over time
Disaggregation of Revenue [Line Items]
Net sales									12,929	10,674	8,437
Ingredient solutions
Disaggregation of Revenue [Line Items]
Net sales									62,034	56,440	53,020
Ingredient solutions | Products transferred at a point in time
Disaggregation of Revenue [Line Items]
Net sales									62,034	56,440	53,020
Premium beverage alcohol | Distillery products
Disaggregation of Revenue [Line Items]
Net sales									188,431	177,998	150,364
Industrial alcohol | Distillery products
Disaggregation of Revenue [Line Items]
Net sales									80,650	76,636	77,290
Food grade alcohol | Distillery products
Disaggregation of Revenue [Line Items]
Net sales									269,081	254,634	227,654
Fuel grade alcohol | Distillery products
Disaggregation of Revenue [Line Items]
Net sales									6,347	6,368	7,372
Distillers feed and related co-products | Distillery products
Disaggregation of Revenue [Line Items]
Net sales									25,698	19,332	21,780
Warehouse services | Distillery products
Disaggregation of Revenue [Line Items]
Net sales									12,929	10,674	8,437
Specialty wheat starches | Ingredient solutions
Disaggregation of Revenue [Line Items]
Net sales									28,594	28,092	26,803
Specialty wheat proteins | Ingredient solutions
Disaggregation of Revenue [Line Items]
Net sales									21,098	19,458	18,211
Commodity wheat starch | Ingredient solutions
Disaggregation of Revenue [Line Items]
Net sales									9,223	8,288	7,002
Commodity wheat protein | Ingredient solutions
Disaggregation of Revenue [Line Items]
Net sales									$ 3,119	$ 602	$ 1,004