Business Segments - Schedule of Reconciliation of Revenue and Operating Income by Reportable Segment to Consolidated Results (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Segment Reporting Information [Line Items]
Service revenues	$ 1,563,812	$ 1,833,455	$ 4,919,625	$ 5,511,116
Segment income	129,932	223,695	441,338	691,877
Amortization of intangible assets	720	417	2,162	1,250
Interest income, net	(7,131)	(2,346)	(17,276)	(3,230)
Income before income taxes	136,343	225,624	456,452	693,857
Contract talent solutions
Segment Reporting Information [Line Items]
Service revenues	943,097	1,139,750	3,007,954	3,461,166
Segment income	58,475	120,048	241,937	386,861
Permanent placement talent solutions
Segment Reporting Information [Line Items]
Service revenues	139,931	182,329	445,922	569,207
Segment income	19,055	32,178	64,612	106,257
Protiviti
Segment Reporting Information [Line Items]
Service revenues	480,784	511,376	1,465,749	1,480,743
Segment income	$ 52,402	$ 71,469	$ 134,789	$ 198,759