Business Segment Information - Identifiable Assets by Business Segment (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment reporting information
Restricted cash	$ 160,967	$ 229,013	$ 81,776
Net accounts receivable	756,059	660,775	606,764
Investments	385,743	327,865	305,253
Pharmaceutical inventory	40,818	40,945	58,995
Goodwill	1,018,156	1,006,288	742,054
Other intangible assets, net	231,883	268,288	186,232
Pharmacy Management
Segment reporting information
Goodwill	395,552	395,421
Operating segments | Healthcare
Segment reporting information
Restricted cash	157,437	220,786	81,608
Net accounts receivable	290,564	244,486	191,058
Investments	378,706	327,865	293,034
Goodwill	622,604	610,867	350,576
Other intangible assets, net	136,644	165,159	55,756
Operating segments | Pharmacy Management
Segment reporting information
Restricted cash	576	8,059	1
Net accounts receivable	465,345	403,880	405,611
Investments	7,037		10,703
Pharmaceutical inventory	40,818	40,945	58,995
Goodwill	395,552	395,421	391,478
Other intangible assets, net	82,072	103,129	130,476
Corporate and Elimination
Segment reporting information
Restricted cash	2,954	168	167
Net accounts receivable	150	$ 12,409	10,095
Investments			$ 1,516
Other intangible assets, net	$ 13,167