Significant Accounting Policies - Schedule of Property and Equipment Recorded at Cost and Depreciated on Straight-line Basis Over Estimated Useful Lives (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 104,425	$ 89,973
Less: Accumulated depreciation	(63,102)	(46,277)
Property and equipment, net	41,323	43,696
Computer Software
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 60,707	46,636
Computer Software | Minimum
Property Plant And Equipment [Line Items]
Estimated useful lives	18 months
Computer Software | Maximum
Property Plant And Equipment [Line Items]
Estimated useful lives	5 years
Computer Hardware
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 20,197	19,429
Computer Hardware | Minimum
Property Plant And Equipment [Line Items]
Estimated useful lives	3 years
Computer Hardware | Maximum
Property Plant And Equipment [Line Items]
Estimated useful lives	5 years
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 4,634	4,757
Estimated useful lives	10 years
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 18,887	$ 19,151
Estimated useful lives	Lesser of useful life or lease term