Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Net sales	$ 189,349	$ 196,934	$ 565,801	$ 609,099
U.S.
Disaggregation of Revenue [Line Items]
Net sales	123,579	130,126	366,276	400,409
Canada
Disaggregation of Revenue [Line Items]
Net sales	6,088	8,553	20,179	25,208
Mexico
Disaggregation of Revenue [Line Items]
Net sales	33,031	32,276	101,563	98,034
Other Countries
Disaggregation of Revenue [Line Items]
Net sales	26,651	25,979	77,783	85,448
Specialty Ingredients
Disaggregation of Revenue [Line Items]
Net sales	127,654	139,289	387,538	435,513
Specialty Ingredients | U.S.
Disaggregation of Revenue [Line Items]
Net sales	98,909	105,127	292,772	332,525
Specialty Ingredients | Canada
Disaggregation of Revenue [Line Items]
Net sales	3,773	6,726	12,950	19,005
Specialty Ingredients | Mexico
Disaggregation of Revenue [Line Items]
Net sales	8,438	9,754	25,904	26,472
Specialty Ingredients | Other Countries
Disaggregation of Revenue [Line Items]
Net sales	16,534	17,682	55,912	57,511
Core Ingredients
Disaggregation of Revenue [Line Items]
Net sales	51,353	45,292	144,565	137,421
Core Ingredients | U.S.
Disaggregation of Revenue [Line Items]
Net sales	15,626	14,431	46,694	43,120
Core Ingredients | Canada
Disaggregation of Revenue [Line Items]
Net sales	2,137	1,704	6,832	5,947
Core Ingredients | Mexico
Disaggregation of Revenue [Line Items]
Net sales	23,493	21,005	69,471	60,988
Core Ingredients | Other Countries
Disaggregation of Revenue [Line Items]
Net sales	10,097	8,152	21,568	27,366
Co-Products & Other
Disaggregation of Revenue [Line Items]
Net sales	10,342	12,353	33,698	36,165
Co-Products & Other | U.S.
Disaggregation of Revenue [Line Items]
Net sales	9,044	10,568	26,810	24,764
Co-Products & Other | Canada
Disaggregation of Revenue [Line Items]
Net sales	178	123	397	256
Co-Products & Other | Mexico
Disaggregation of Revenue [Line Items]
Net sales	1,100	1,517	6,188	10,574
Co-Products & Other | Other Countries
Disaggregation of Revenue [Line Items]
Net sales	$ 20	$ 145	$ 303	$ 571