Property and Equipment, Net - Components of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	$ 2,717,948	$ 2,102,164
Less: accumulated depreciation	(1,575,879)	(1,201,744)
Projects in progress	252,835	163,839
Property and equipment, net	1,394,904	1,064,259
Capitalized software development
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	1,606,960	1,220,822
Computer equipment
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	665,652	485,074
Furniture and other equipment
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	72,811	65,939
Buildings and leasehold improvements
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	241,713	199,604
Land
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	130,812	$ 130,725
Build To Suit Asset
Property, Plant and Equipment [Line Items]
Projects in progress	$ 38,000