Property and Equipment, Net - Components of Property and Equipment (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Computer hardware	$ 155,293	$ 159,309
Computer software	335,710	312,968
Furniture and equipment	104,665	105,262
Leasehold improvements	112,990	113,782
Other	9,300	9,045
Property and equipment, cost	717,958	700,366
Accumulated depreciation	(588,729)	(578,612)
Property and equipment, net	$ 129,229	$ 121,754