Accounts Receivable, Sales and Allowances - Net Trade Accounts Receivable (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Receivables [Abstract]
Gross Accounts Receivable	$ 310,007	$ 258,173
Less reserves for:
Chargebacks	(43,642)	(40,498)
Rebates	(38,284)	(42,515)
Product returns	(31,588)	(33,127)
Discounts and allowances	(7,393)	(5,816)
Advertising and promotions	(1,335)	(1,508)
Doubtful accounts	(547)	(536)
Trade accounts receivable, net	$ 187,218	$ 134,173