Revenue Recognition - Schedule of Revenue Disaggregated by Functional Specialization and Segments (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) segment	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Revenue from Contract with Customer [Abstract]
Number of reportable segments | segment	3
Guarantee period	90 days
Disaggregation of Revenue [Line Items]
Service revenues	$ 6,392,517	$ 7,238,142	$ 6,461,444
Elimination of intersegment revenues
Disaggregation of Revenue [Line Items]
Service revenues	(442,326)	(552,231)	(580,379)
Finance and accounting
Disaggregation of Revenue [Line Items]
Service revenues	2,811,093	3,185,183	2,764,897
Administration and customer support
Disaggregation of Revenue [Line Items]
Service revenues	816,409	1,042,634	1,058,906
Technology
Disaggregation of Revenue [Line Items]
Service revenues	710,156	857,261	795,319
Total contract talent solutions
Disaggregation of Revenue [Line Items]
Service revenues	3,895,332	4,532,847	4,038,743
Permanent placement talent solutions
Disaggregation of Revenue [Line Items]
Service revenues	567,486	725,155	569,921
Protiviti
Disaggregation of Revenue [Line Items]
Service revenues	$ 1,929,699	$ 1,980,140	$ 1,852,780