Revenue Recognition - Schedule of Revenue Disaggregated by Line of Business (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Disaggregation of Revenue [Line Items]
Total service revenues	$ 1,369,743	$ 1,472,524	$ 2,721,650	$ 2,948,461
Total contract talent solutions
Disaggregation of Revenue [Line Items]
Total service revenues	759,808	854,897	1,523,013	1,741,955
Permanent placement talent solutions
Disaggregation of Revenue [Line Items]
Total service revenues	114,713	131,063	226,804	255,830
Protiviti
Disaggregation of Revenue [Line Items]
Total service revenues	495,222	486,564	971,833	950,676
Elimination of intersegment revenues | Total contract talent solutions
Disaggregation of Revenue [Line Items]
Total service revenues	(119,812)	(116,466)	(237,709)	(229,280)
Finance and accounting | Total contract talent solutions
Disaggregation of Revenue [Line Items]
Total service revenues	555,626	623,120	1,118,559	1,265,090
Administrative and customer support | Total contract talent solutions
Disaggregation of Revenue [Line Items]
Total service revenues	165,591	190,344	331,218	390,276
Technology | Total contract talent solutions
Disaggregation of Revenue [Line Items]
Total service revenues	$ 158,403	$ 157,899	$ 310,945	$ 315,869