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, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Segment Reporting [Line Items]
Service revenues	$ 1,359,297	$ 1,354,477	$ 3,995,841	$ 4,076,127
Segment costs of services	827,940	839,826	2,489,164	2,544,195
Compensation expenses	322,810	314,321	964,288	971,620
Other	135,995	139,121	402,574	421,198
Segment selling, general and administrative expenses	458,805	453,442	1,366,862	1,392,818
Segment income	72,552	61,209	139,815	139,114
Interest income, net	(2,114)	(2,510)	(6,885)	(8,321)
Income before income taxes	74,666	63,719	146,700	147,435
Service revenues	(1,359,297)	(1,354,477)	(3,995,841)	(4,076,127)
Contract talent solutions
Segment Reporting [Line Items]
Service revenues	758,830	746,223	2,231,251	2,269,236
Segment costs of services	460,600	456,102	1,358,846	1,384,815
Compensation expenses	211,315	205,902	628,577	636,778
Other	64,386	67,853	194,182	206,163
Segment selling, general and administrative expenses	275,701	273,755	822,759	842,941
Segment income	22,529	16,366	49,646	41,480
Service revenues	(758,830)	(746,223)	(2,231,251)	(2,269,236)
Contract talent solutions | Elimination of intersegment revenues
Segment Reporting [Line Items]
Service revenues	(126,179)	(123,681)	(364,387)	(361,390)
Service revenues	126,179	123,681	364,387	361,390
Permanent placement talent solutions
Segment Reporting [Line Items]
Service revenues	116,946	110,125	343,941	336,929
Segment costs of services	270	222	716	614
Compensation expenses	86,325	83,885	261,188	260,529
Other	17,623	18,407	52,359	56,292
Segment selling, general and administrative expenses	103,948	102,292	313,547	316,821
Segment income	12,728	7,611	29,678	19,494
Service revenues	(116,946)	(110,125)	(343,941)	(336,929)
Protiviti
Segment Reporting [Line Items]
Service revenues	483,521	498,129	1,420,649	1,469,962
Segment costs of services	367,070	383,502	1,129,602	1,158,766
Compensation expenses	25,170	24,534	74,523	74,313
Other	53,986	52,861	156,033	158,743
Segment selling, general and administrative expenses	79,156	77,395	230,556	233,056
Segment income	37,295	37,232	60,491	78,140
Service revenues	(483,521)	(498,129)	(1,420,649)	(1,469,962)
Contract Talent Solutions And Protiviti | Elimination of intersegment revenues
Segment Reporting [Line Items]
Service revenues	(126,200)	(123,700)	(364,400)	(361,400)
Service revenues	$ 126,200	$ 123,700	$ 364,400	$ 361,400