Summary of Significant Accounting Policies - Schedule of Estimated Useful Lives of Long-Lived Assets (Details)	6 Months Ended
	Jun. 30, 2019
Building
Estimated Useful Lives Of Long Lived Assets [Line Items]
Property and equipment, estimated useful life	40 years
Computer Equipment | Minimum
Estimated Useful Lives Of Long Lived Assets [Line Items]
Property and equipment, estimated useful life	2 years
Computer Equipment | Maximum
Estimated Useful Lives Of Long Lived Assets [Line Items]
Property and equipment, estimated useful life	5 years
Furniture, Fixtures, and Other Assets
Estimated Useful Lives Of Long Lived Assets [Line Items]
Property and equipment, estimated useful life	5 years
Leasehold Improvements
Estimated Useful Lives Of Long Lived Assets [Line Items]
Property and equipment, estimated useful life	Shorter of remaining lease term or 5 years
Leasehold Improvements | Maximum
Estimated Useful Lives Of Long Lived Assets [Line Items]
Property and equipment, estimated useful life	5 years
Purchased software
Estimated Useful Lives Of Long Lived Assets [Line Items]
Property and equipment, estimated useful life	3 years
Capitalized Internal-Use Software
Estimated Useful Lives Of Long Lived Assets [Line Items]
Acquisition intangible assets, estimated useful life	3 years
Customer Relationships | Minimum
Estimated Useful Lives Of Long Lived Assets [Line Items]
Acquisition intangible assets, estimated useful life	3 years
Customer Relationships | Maximum
Estimated Useful Lives Of Long Lived Assets [Line Items]
Acquisition intangible assets, estimated useful life	7 years
Trade Name | Minimum
Estimated Useful Lives Of Long Lived Assets [Line Items]
Acquisition intangible assets, estimated useful life	2 years
Trade Name | Maximum
Estimated Useful Lives Of Long Lived Assets [Line Items]
Acquisition intangible assets, estimated useful life	10 years
Technology | Minimum
Estimated Useful Lives Of Long Lived Assets [Line Items]
Acquisition intangible assets, estimated useful life	3 years
Technology | Maximum
Estimated Useful Lives Of Long Lived Assets [Line Items]
Acquisition intangible assets, estimated useful life	8 years