Accounts Receivable, Sales and Allowances - Adjustments to Gross Sales (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Receivables [Abstract]
Gross sales	$ 507,819	$ 567,112	$ 1,028,352	$ 1,247,647
Less adjustments for:
Chargebacks	(222,482)	(237,275)	(446,445)	(517,437)
Rebates, administrative and other fees	(75,094)	(109,760)	(167,374)	(234,138)
Product returns	(6,133)	(8,116)	(13,254)	(16,533)
Discounts and allowances	(9,946)	(10,830)	(20,183)	(23,752)
Advertising, promotions and others	(3,220)	(1,991)	(6,089)	(3,227)
Revenues, net	$ 190,944	$ 199,140	$ 375,007	$ 452,560

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130543-203045

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130539-203045

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130545-203045

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration