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, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Segment Reporting Information [Line Items]
Service revenues	$ 1,354,477	$ 1,465,004	$ 4,076,127	$ 4,413,465
Segment costs of services	839,826	887,258	2,544,195	2,684,656
Compensation expenses	314,321	332,276	971,620	1,016,344
Other	139,121	155,675	421,198	447,120
Segment selling, general and administrative expenses	453,442	487,951	1,392,818	1,463,464
Segment income	61,209	89,795	139,114	265,345
Interest income, net	(2,510)	(5,391)	(8,321)	(16,990)
Income before income taxes	63,719	95,186	147,435	282,335
Service revenues	(1,354,477)	(1,465,004)	(4,076,127)	(4,413,465)
Contract talent solutions
Segment Reporting Information [Line Items]
Service revenues	746,223	830,403	2,269,236	2,572,358
Segment costs of services	456,102	507,368	1,384,815	1,562,592
Compensation expenses	205,902	218,931	636,778	668,947
Other	67,853	78,260	206,163	226,711
Segment selling, general and administrative expenses	273,755	297,191	842,941	895,658
Segment income	16,366	25,844	41,480	114,108
Service revenues	(746,223)	(830,403)	(2,269,236)	(2,572,358)
Contract talent solutions | Elimination of intersegment revenues
Segment Reporting Information [Line Items]
Service revenues	(123,681)	(122,321)	(361,390)	(351,601)
Service revenues	123,681	122,321	361,390	351,601
Permanent placement talent solutions
Segment Reporting Information [Line Items]
Service revenues	110,125	123,275	336,929	379,105
Segment costs of services	222	271	614	752
Compensation expenses	83,885	90,450	260,529	277,120
Other	18,407	20,367	56,292	61,043
Segment selling, general and administrative expenses	102,292	110,817	316,821	338,163
Segment income	7,611	12,187	19,494	40,190
Service revenues	(110,125)	(123,275)	(336,929)	(379,105)
Protiviti
Segment Reporting Information [Line Items]
Service revenues	498,129	511,326	1,469,962	1,462,002
Segment costs of services	383,502	379,619	1,158,766	1,121,312
Compensation expenses	24,534	22,895	74,313	70,277
Other	52,861	57,048	158,743	159,366
Segment selling, general and administrative expenses	77,395	79,943	233,056	229,643
Segment income	37,232	51,764	78,140	111,047
Service revenues	(498,129)	(511,326)	(1,469,962)	(1,462,002)
Contract Talent Solutions And Protiviti | Elimination of intersegment revenues
Segment Reporting Information [Line Items]
Service revenues	(123,700)	(122,300)	(361,400)	(351,600)
Service revenues	$ 123,700	$ 122,300	$ 361,400	$ 351,600