Revenue Recognition - Schedule of Revenue Disaggregated by Functional Specialization and Segments (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($) segment	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Revenue from Contract with Customer [Abstract]
Number of reportable segments | segment	3
Guarantee period	90 days
Disaggregation of Revenue [Line Items]
Service revenues	$ 7,238,142	$ 6,461,444	$ 5,109,000
Elimination of intersegment revenues
Disaggregation of Revenue [Line Items]
Service revenues	(552,231)	(580,379)	(239,996)
Finance and accounting
Disaggregation of Revenue [Line Items]
Service revenues	3,185,183	2,764,897	2,256,966
Administration and customer support
Disaggregation of Revenue [Line Items]
Service revenues	1,042,634	1,058,906	764,947
Technology
Disaggregation of Revenue [Line Items]
Service revenues	857,261	795,319	695,418
Total contract talent solutions
Disaggregation of Revenue [Line Items]
Service revenues	4,532,847	4,038,743	3,477,335
Permanent placement talent solutions
Disaggregation of Revenue [Line Items]
Service revenues	725,155	569,921	370,109
Protiviti
Disaggregation of Revenue [Line Items]
Service revenues	$ 1,980,140	$ 1,852,780	$ 1,261,556