Revenue Recognition - Schedule of Revenue Disaggregated by Line of Business (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Disaggregation of Revenue [Line Items]
Total service revenues	$ 1,359,297	$ 1,354,477	$ 3,995,841	$ 4,076,127
Total contract talent solutions
Disaggregation of Revenue [Line Items]
Total service revenues	758,830	746,223	2,231,251	2,269,236
Permanent placement talent solutions
Disaggregation of Revenue [Line Items]
Total service revenues	116,946	110,125	343,941	336,929
Protiviti
Disaggregation of Revenue [Line Items]
Total service revenues	483,521	498,129	1,420,649	1,469,962
Elimination of intersegment revenues | Total contract talent solutions
Disaggregation of Revenue [Line Items]
Total service revenues	(126,179)	(123,681)	(364,387)	(361,390)
Finance and accounting | Total contract talent solutions
Disaggregation of Revenue [Line Items]
Total service revenues	565,593	553,364	1,656,068	1,671,923
Administrative and customer support | Total contract talent solutions
Disaggregation of Revenue [Line Items]
Total service revenues	154,365	158,689	458,559	489,907
Technology | Total contract talent solutions
Disaggregation of Revenue [Line Items]
Total service revenues	$ 165,051	$ 157,851	$ 481,011	$ 468,796