SEGMENT INFORMATION - Depreciation/Amortization (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Depreciation/amortization	$ 43,986	$ 43,905	$ 45,676
Human Nutrition & Health | Operating Segments
Segment Reporting Information [Line Items]
Depreciation/amortization	33,594	33,384	33,796
Animal Nutrition & Health | Operating Segments
Segment Reporting Information [Line Items]
Depreciation/amortization	5,606	5,618	7,243
Specialty Products | Operating Segments
Segment Reporting Information [Line Items]
Depreciation/amortization	4,092	4,097	3,787
Industrial Products | Operating Segments
Segment Reporting Information [Line Items]
Depreciation/amortization	$ 694	$ 806	$ 850