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, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Segment Reporting Information [Line Items]
Service revenues	$ 1,465,004	$ 1,563,812	$ 4,413,465	$ 4,919,625
Segment income	90,100	129,932	266,258	441,338
Amortization of intangible assets	305	720	913	2,162
Interest income, net	(5,391)	(7,131)	(16,990)	(17,276)
Income before income taxes	95,186	136,343	282,335	456,452
Contract talent solutions
Segment Reporting Information [Line Items]
Service revenues	830,403	943,097	2,572,358	3,007,954
Segment income	25,844	58,475	114,108	241,937
Permanent placement talent solutions
Segment Reporting Information [Line Items]
Service revenues	123,275	139,931	379,105	445,922
Segment income	12,187	19,055	40,190	64,612
Protiviti
Segment Reporting Information [Line Items]
Service revenues	511,326	480,784	1,462,002	1,465,749
Segment income	$ 52,069	$ 52,402	$ 111,960	$ 134,789