Property and Equipment, Net - Components of Property and Equipment, Net (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	$ 366,375	$ 363,532
Less accumulated depreciation	(100,254)	(94,093)
Total property and equipment, net	266,121	269,439
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	28,356	27,046
Land [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	89,130	89,130
Building [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	197,343	197,689
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	10,783	10,494
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	8,712	8,071
Software [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	$ 32,051	$ 31,102