General - Revenues and Significant Customers (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Net revenues
Managed Care Revenue	$ 559,100	$ 545,000
Fee-For-Service, Fixed Fee and Cost-Plus Contracts Revenue	143,700	103,000
Rebate Revenues	22,300	19,800
PBM Revenue	432,900	344,500
Dispensing Revenue	55,200	55,300
Medicare Part D Revenues	111,600	50,300
Co-payments	23,400	9,500
Medicare Part D Receivables	126,700		$ 117,500
Revenues	$ 1,305,623	1,117,022
Florida Medicaid Contract
Net revenues
Termination notice	1 day
Termination notice period without cause	30 days
Florida Contracts
Net revenues
Revenues	$ 145,700	130,800
Pharmacy Management | Customer A
Net revenues
Revenues	1,730	$ 99,959
Pharmacy Management | Customer B
Net revenues
Revenues	$ 92,712