Accounts Receivable (Schedule of Accounts Receivable) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2013	Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross trade accounts receivable	$ 489,028	$ 383,347
Deductions from trade accounts receivable	(314,860)	(240,061)	(224,760)	(195,702)
Allowance for doubtful accounts	(233)	(7)	(2)	0
Accounts receivable, net	173,935	143,279
Chargebacks [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Deductions from trade accounts receivable	(60,341)	(48,766)	(48,721)	(41,670)
Rebates and incentive programs [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Deductions from trade accounts receivable	(107,445)	(75,321)	(66,628)	(59,426)
Returns [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Deductions from trade accounts receivable	(87,720)	(78,181)	(77,400)	(68,062)
Cash discounts and other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Deductions from trade accounts receivable	$ (59,354)	$ (37,793)	$ (32,011)	$ (26,544)