Property and Equipment, Net - Components of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	$ 3,265,716	$ 2,717,948
Less: accumulated depreciation	(2,055,720)	(1,575,879)
Projects in progress	365,262	252,835
Property and equipment, net	1,575,258	1,394,904
Capitalized software development
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	2,111,262	1,606,960
Computer equipment
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	658,031	665,652
Furniture and other equipment
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	84,509	72,811
Buildings and leasehold improvements
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	282,865	241,713
Land
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	129,049	130,812
Build To Suit Asset
Property, Plant and Equipment [Line Items]
Projects in progress	$ 111,000	$ 38,000

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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-Name Accounting Standards Codification
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Amount of structure or a modification to a structure under construction. Includes recently completed structures or modifications to structures that have not been placed into service.

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