Business Segments - Schedule of Reconciliation of Revenue and Operating Income by Reportable Segment to Consolidated Results (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Segment Reporting Information [Line Items]
Service revenues	$ 1,472,524	$ 1,639,478	$ 2,948,461	$ 3,355,813
Segment income	91,580	146,612	176,158	311,406
Amortization of intangible assets	304	721	608	1,442
Interest income, net	(5,186)	(5,320)	(11,599)	(10,145)
Income before income taxes	96,462	151,211	187,149	320,109
Contract talent solutions
Segment Reporting Information [Line Items]
Service revenues	854,897	999,383	1,741,955	2,064,857
Segment income	38,146	81,316	88,264	183,462
Permanent placement talent solutions
Segment Reporting Information [Line Items]
Service revenues	131,063	149,254	255,830	305,991
Segment income	16,148	21,730	28,003	45,557
Protiviti
Segment Reporting Information [Line Items]
Service revenues	486,564	490,841	950,676	984,965
Segment income	$ 37,286	$ 43,566	$ 59,891	$ 82,387