Property and Equipment, Net - Components of Property and Equipment (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Computer hardware	$ 172,880	$ 170,746
Computer software	378,076	374,490
Furniture and equipment	99,805	100,472
Leasehold improvements	137,536	133,541
Other	10,241	9,993
Property and equipment, cost	798,538	789,242
Accumulated depreciation	(640,756)	(627,733)
Property and equipment, net	$ 157,782	$ 161,509