Business Segments - Reconciliation of Revenue and Operating Income by Reportable Segment to Consolidated Results (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Segment Reporting Information [Line Items]
Service revenues	$ 1,369,743	$ 1,472,524	$ 2,721,650	$ 2,948,461
Segment costs of services	847,468	892,615	1,704,369	1,797,398
Compensation expenses	322,376	340,401	657,300	684,069
Other	140,705	148,232	282,076	291,444
Segment selling, general and administrative expenses	463,081	488,633	939,376	975,513
Segment income	59,194	91,276	77,905	175,550
Interest income, net	(2,239)	(5,186)	(5,811)	(11,599)
Income before income taxes	61,433	96,462	83,716	187,149
Service revenues	(1,369,743)	(1,472,524)	(2,721,650)	(2,948,461)
Depreciation	12,602	12,516	25,608	25,520
Contract talent solutions
Segment Reporting Information [Line Items]
Service revenues	759,808	854,897	1,523,013	1,741,955
Segment costs of services	462,441	518,736	928,713	1,055,224
Compensation expenses	209,895	222,298	430,876	450,017
Other	69,049	75,717	138,310	148,450
Segment selling, general and administrative expenses	278,944	298,015	569,186	598,467
Segment income	18,423	38,146	25,114	88,264
Service revenues	(759,808)	(854,897)	(1,523,013)	(1,741,955)
Depreciation	6,219	6,364	12,717	12,957
Contract talent solutions | Elimination of intersegment revenues
Segment Reporting Information [Line Items]
Service revenues	(119,812)	(116,466)	(237,709)	(229,280)
Service revenues	119,812	116,466	237,709	229,280
Permanent placement talent solutions
Segment Reporting Information [Line Items]
Service revenues	114,713	131,063	226,804	255,830
Segment costs of services	162	262	392	481
Compensation expenses	87,744	94,348	176,644	186,670
Other	18,548	20,305	37,885	40,676
Segment selling, general and administrative expenses	106,292	114,653	214,529	227,346
Segment income	8,259	16,148	11,883	28,003
Service revenues	(114,713)	(131,063)	(226,804)	(255,830)
Depreciation	2,043	2,047	4,141	4,271
Protiviti
Segment Reporting Information [Line Items]
Service revenues	495,222	486,564	971,833	950,676
Segment costs of services	384,865	373,617	775,264	741,693
Compensation expenses	24,737	23,755	49,780	47,382
Other	53,108	52,210	105,881	102,318
Segment selling, general and administrative expenses	77,845	75,965	155,661	149,700
Segment income	32,512	36,982	40,908	59,283
Service revenues	(495,222)	(486,564)	(971,833)	(950,676)
Depreciation	4,340	4,105	8,750	8,292
Contract Talent Solutions And Protiviti | Elimination of intersegment revenues
Segment Reporting Information [Line Items]
Service revenues	(119,800)	(116,500)	(237,700)	(229,300)
Service revenues	$ 119,800	$ 116,500	$ 237,700	$ 229,300