SEGMENT INFORMATION - Business Segment Net Sales (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Net sales	$ 703,644	$ 643,705	$ 643,679
Other and Unallocated
Segment Reporting Information [Line Items]
Net sales	7,557	26,458	50,941
Transaction and integration related costs	2,410	3,436	1,786
Human Nutrition & Health | Operating Segments
Segment Reporting Information [Line Items]
Net sales	400,330	347,433	341,237
Animal Nutrition & Health | Operating Segments
Segment Reporting Information [Line Items]
Net sales	192,191	177,557	175,693
Specialty Products | Operating Segments
Segment Reporting Information [Line Items]
Net sales	$ 103,566	$ 92,257	$ 75,808