Property and Equipment - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 2,346,982	$ 2,084,707
Accumulated depreciation and amortization	(1,484,447)	(1,283,690)
Property and equipment, net	862,535	801,017
Computer and networking equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,292,587	1,170,471
Purchased software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	61,276	51,727
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 48,521	41,968
Estimated useful life (in years)	5 years
Office equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 26,949	24,497
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	152,487	139,991
Internal-use software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 765,162	$ 656,053
Minimum \| Computer and networking equipment
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	3 years
Minimum \| Purchased software
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	3 years
Minimum \| Office equipment
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	3 years
Minimum \| Leasehold improvements
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	1 year
Minimum \| Internal-use software
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	2 years
Maximum \| Computer and networking equipment
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	7 years
Maximum \| Purchased software
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	10 years
Maximum \| Office equipment
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	5 years
Maximum \| Leasehold improvements
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	16 years
Maximum \| Internal-use software
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	7 years

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.14)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(13))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(14))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
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-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(8))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

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-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

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Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

+ References

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