Business Segments - Reconciliation of Revenue and Operating Income by Reportable Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Segment Reporting Information [Line Items]
Service revenues	$ 1,716,335	$ 1,814,834
Segment income	164,794	227,651
Amortization of intangible assets	721	417
Interest income, net	(4,825)	(166)
Income before income taxes	168,898	227,400
Contract talent solutions
Segment Reporting Information [Line Items]
Service revenues	1,065,474	1,155,723
Segment income	102,146	133,246
Permanent placement talent solutions
Segment Reporting Information [Line Items]
Service revenues	156,737	186,782
Segment income	23,827	37,328
Protiviti
Segment Reporting Information [Line Items]
Service revenues	494,124	472,329
Segment income	$ 38,821	$ 57,077