Accounts Receivable, Sales and Allowances - Adjustments to Gross Sales (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Receivables [Abstract]
Gross sales	$ 466,009	$ 507,819	$ 924,649	$ 1,028,352
Less adjustments for:
Chargebacks	(192,717)	(222,482)	(398,111)	(446,445)
Rebates, administrative and other fees	(77,969)	(75,094)	(142,233)	(167,374)
Product returns	(5,471)	(6,133)	(17,373)	(13,254)
Discounts and allowances	(9,025)	(9,946)	(18,075)	(20,183)
Advertising, promotions and others	(2,769)	(3,220)	(4,929)	(6,089)
Revenues, net	$ 178,057	$ 190,944	$ 343,928	$ 375,007