Revenue Recognition - Schedule of Revenue Disaggregated by Line of Business (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2023 USD ($) segment	Sep. 30, 2022 USD ($)
Revenue from Contract with Customer [Abstract]
Number of reportable segments | segment			3
Guarantee period			90 days
Disaggregation of Revenue [Line Items]
Total service revenues	$ 1,563,812	$ 1,833,455	$ 4,919,625	$ 5,511,116
Elimination of intersegment revenues
Disaggregation of Revenue [Line Items]
Total service revenues	(100,630)	(132,745)	(341,228)	(414,493)
Finance and accounting
Disaggregation of Revenue [Line Items]
Total service revenues	676,588	805,229	2,175,812	2,417,829
Administrative and customer support
Disaggregation of Revenue [Line Items]
Total service revenues	196,565	250,531	626,938	809,578
Technology
Disaggregation of Revenue [Line Items]
Total service revenues	170,574	216,735	546,432	648,252
Total contract talent solutions
Disaggregation of Revenue [Line Items]
Total service revenues	943,097	1,139,750	3,007,954	3,461,166
Permanent placement talent solutions
Disaggregation of Revenue [Line Items]
Total service revenues	139,931	182,329	445,922	569,207
Protiviti
Disaggregation of Revenue [Line Items]
Total service revenues	$ 480,784	$ 511,376	$ 1,465,749	$ 1,480,743