Acquisitions - Schedule of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Mar. 01, 2021	Mar. 31, 2021	Dec. 31, 2020
Business Acquisition [Line Items]
Goodwill		$ 679,559	$ 609,457
Client relationships
Business Acquisition [Line Items]
Intangible assets, useful life	3 years 6 months
Trademarks
Business Acquisition [Line Items]
Intangible assets, useful life	3 years 6 months
Acquisition
Business Acquisition [Line Items]
Total cash consideration	$ 214,984
Consideration transferred to acquire business	214,984
Cash and cash equivalents	40,794
Accounts receivable and other current assets	88,529
Other assets	11,801
Fixed assets and capitalized software	40,957
Accounts payable	(31,163)
Accrued liabilities	(39,654)
Contract liabilities	(27,075)
Other current liabilities	(11,641)
Deferred tax liabilities	(40,497)
Other liabilities	(15,505)
Total identifiable net assets	143,262
Goodwill	71,722
Total net assets acquired	214,984
Acquisition | Client relationships
Business Acquisition [Line Items]
Intangible assets	101,839
Acquisition | Trademarks
Business Acquisition [Line Items]
Intangible assets	$ 24,877