Reportable Segments - Schedule (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting Information [Line Items]
Revenue	$ 402,725	$ 365,424	$ 1,169,564	$ 1,043,652
Gross profit	119,264	103,878	336,877	295,763
Operating and other expenses	91,446	78,098	260,882	243,441
Income from operations, before income taxes	27,818	25,780	75,995	52,322
Tech
Segment Reporting Information [Line Items]
Revenue	337,230	260,251	927,518	782,785
Gross profit	95,934	71,960	258,449	216,606
FA
Segment Reporting Information [Line Items]
Revenue	65,495	105,173	242,046	260,867
Gross profit	$ 23,330	$ 31,918	$ 78,428	$ 79,157