Goodwill and Identifiable Assets (Goodwill) (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2014	Dec. 31, 2013
Goodwill [Roll Forward]
Gross goodwill	$ 878,862	$ 512,060	$ 514,426
Goodwill	878,862	512,060
Translation adjustment	(1,048)	(2,366)
Apex
Goodwill [Roll Forward]
Gross goodwill	648,696	287,951	289,712
Translation adjustment	(1,001)	(1,761)
Oxford
Goodwill [Roll Forward]
Gross goodwill	230,166	224,109	$ 224,714
Translation adjustment	(47)	$ (605)
Creative Circle [Member]
Goodwill [Roll Forward]
Goodwill, Acquired During Period	361,746
LabResource [Member]
Goodwill [Roll Forward]
Goodwill, Acquired During Period	$ 6,104