CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Income Statement [Abstract]
Revenue from Contract with Customer, Product and Service [Extensible List]	Service [Member]	Service [Member]	Service [Member]	Service [Member]
Revenue from services	$ 753,561	$ 331,827	$ 1,542,293	$ 661,068
Operating expenses:
Direct operating expenses	583,156	259,237	1,197,094	517,013
Selling, general and administrative expenses	86,009	50,344	162,822	96,671
Bad debt expense	3,192	466	5,561	970
Depreciation and amortization	3,481	2,199	6,200	4,452
Acquisition and integration-related costs	0	924	40	924
Restructuring (benefits) costs	(1,114)	835	(634)	2,073
Impairment charges	0	1,921	1,741	2,070
Total operating expenses	674,724	315,926	1,372,824	624,173
Income from operations	78,837	15,901	169,469	36,895
Other expenses (income):
Interest expense	3,857	1,196	7,378	1,867
Loss on early extinguishment of debt	1,912	0	1,912	0
Other income, net	(1,084)	(204)	(1,092)	(241)
Income before income taxes	74,152	14,909	161,271	35,269
Income tax expense	21,258	3,361	46,394	4,273
Net income attributable to common stockholders	52,894	11,548	114,877	30,996
Other comprehensive income:
Unrealized foreign currency translation loss, net of tax	(31)	(24)	(42)	(30)
Comprehensive income	$ 52,863	$ 11,524	$ 114,835	$ 30,966
Net income per share attributable to common stockholders - Basic (in dollars per share)	$ 1.41	$ 0.32	$ 3.08	$ 0.85
Net income per share attributable to common stockholders - Diluted (in dollars per share)	$ 1.40	$ 0.31	$ 3.03	$ 0.84
Weighted average common shares outstanding:
Basic (shares)	37,471	36,625	37,251	36,404
Diluted (shares)	37,757	37,203	37,866	37,120