Accounts Receivable, Sales and Allowances - Net Trade Accounts Receivable (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Receivables [Abstract]
Gross Accounts Receivable	$ 258,173	$ 308,305	$ 378,759
Less reserves for:
Chargebacks	(40,498)	(55,312)
Rebates	(42,515)	(55,963)
Product returns	(33,127)	(35,146)
Discounts and allowances	(5,816)	(6,561)
Advertising and promotions	(1,508)	(1,574)
Doubtful accounts	(536)	(623)
Trade accounts receivable, net	$ 134,173	$ 153,126