Business Segment Information - Identifiable Assets by Business Segment (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment reporting information
Restricted cash and cash equivalents	$ 81,776	$ 133,597	$ 215,325
Net accounts receivable	606,764	428,644	353,713
Investments	305,253	326,165	267,654
Pharmaceutical inventory	58,995	50,749	39,375
Goodwill	742,054	621,390	566,106
Other intangible assets, net	186,232	133,374	133,718
Operating segments | Healthcare
Segment reporting information
Restricted cash and cash equivalents	81,608	133,597	213,681
Net accounts receivable	191,058	153,036	170,488
Investments	293,034	313,045	142,957
Goodwill	350,576	260,618	254,470
Other intangible assets, net	55,756	12,227	10,840
Operating segments | Pharmacy Management
Segment reporting information
Restricted cash and cash equivalents	1
Net accounts receivable	405,611	270,975	180,535
Investments	10,703
Pharmaceutical inventory	58,995	50,749	39,375
Goodwill	391,478	360,772	311,636
Other intangible assets, net	130,476	121,147	122,878
Corporate and Elimination
Segment reporting information
Restricted cash and cash equivalents	167		1,644
Net accounts receivable	10,095	4,633	2,690
Investments	$ 1,516	$ 13,120	$ 124,697