Disaggregation of Revenue - Schedule of Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disaggregation of Revenue [Line Items]
Revenue	$ 1,710,765	$ 1,579,922	$ 1,397,700
Flex revenue
Disaggregation of Revenue [Line Items]
Revenue	1,652,450	1,530,157	1,364,097
Direct Hire revenue
Disaggregation of Revenue [Line Items]
Revenue	58,315	49,765	33,603
Technology
Disaggregation of Revenue [Line Items]
Revenue	1,507,627	1,273,941	1,049,628
Technology | Flex revenue
Disaggregation of Revenue [Line Items]
Revenue	1,476,055	1,247,560	1,032,901
Technology | Direct Hire revenue
Disaggregation of Revenue [Line Items]
Revenue	31,572	26,381	16,727
FA
Disaggregation of Revenue [Line Items]
Revenue	203,138	305,981	348,072
FA | Flex revenue
Disaggregation of Revenue [Line Items]
Revenue	176,395	282,597	331,196
FA | Direct Hire revenue
Disaggregation of Revenue [Line Items]
Revenue	$ 26,743	$ 23,384	$ 16,876