Segment Information - Significant Customers (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues, Net | Minimum
Concentration Risk [Line Items]
Concentration risk percentage	10.00%
Accounts Receivable | Minimum
Concentration Risk [Line Items]
Threshold for disclosure of concentration risk	10.00%
Credit Concentration Risk | Revenues, Net | Walgreen Co.
Concentration Risk [Line Items]
Concentration risk percentage	19.00%	20.00%	12.00%
Credit Concentration Risk | Revenues, Net | CVS/Caremark
Concentration Risk [Line Items]
Concentration risk percentage	19.00%	17.00%	10.00%
Credit Concentration Risk | Revenues, Net | Accredo/Curascript
Concentration Risk [Line Items]
Concentration risk percentage	15.00%	15.00%	10.00%
Credit Concentration Risk | Accounts Receivable | Walgreen Co.
Concentration Risk [Line Items]
Concentration risk percentage	15.00%	15.00%
Credit Concentration Risk | Accounts Receivable | CVS/Caremark
Concentration Risk [Line Items]
Concentration risk percentage	17.00%	17.00%
Credit Concentration Risk | Accounts Receivable | Accredo/Curascript
Concentration Risk [Line Items]
Concentration risk percentage	10.00%	16.00%