REVENUE (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2018 USD ($) revenue_sub-stream	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Disaggregation of Revenue [Line Items]
Net sales	$ 163,539	$ 155,043	$ 163,687	$ 161,410	$ 159,264	$ 150,716	$ 147,082	$ 137,728	$ 643,679	$ 594,790	$ 553,204
Number of sub-streams of revenue | revenue_sub-stream									4
United States
Disaggregation of Revenue [Line Items]
Net sales									$ 482,691	460,599	420,821
Foreign Countries
Disaggregation of Revenue [Line Items]
Net sales									160,988	134,191	132,383
Product Sales
Disaggregation of Revenue [Line Items]
Net sales									590,790	542,065	505,174
Co-manufacturing
Disaggregation of Revenue [Line Items]
Net sales									41,348	41,658	39,396
Bill and Hold
Disaggregation of Revenue [Line Items]
Net sales									4,612	4,094	3,061
Consignment
Disaggregation of Revenue [Line Items]
Net sales									2,442	2,333	2,170
Product Sales Revenue
Disaggregation of Revenue [Line Items]
Net sales									639,192	590,150	549,801
Royalty Revenue
Disaggregation of Revenue [Line Items]
Net sales									$ 4,487	$ 4,640	$ 3,403