CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Income Statement [Abstract]
Revenue from Contract with Customer, Product and Service [Extensible List]	Service [Member]	Service [Member]
Revenue from services	$ 788,732	$ 329,241
Operating expenses:
Direct operating expenses	613,938	257,776
Selling, general and administrative expenses	76,813	46,327
Bad debt expense	2,369	504
Depreciation and amortization	2,719	2,253
Acquisition and integration-related costs	40	0
Restructuring costs	480	1,238
Impairment charges	1,741	149
Total operating expenses	698,100	308,247
Income from operations	90,632	20,994
Other expenses (income):
Interest expense	3,521	671
Other income, net	(8)	(37)
Income before income taxes	87,119	20,360
Income tax expense	25,136	912
Net income attributable to common stockholders	61,983	19,448
Other comprehensive income:
Unrealized foreign currency translation loss	(11)	(6)
Comprehensive income	$ 61,972	$ 19,442
Net income per share attributable to common stockholders - Basic (in dollars per share)	$ 1.67	$ 0.54
Net income per share attributable to common stockholders - Diluted (in dollars per share)	$ 1.63	$ 0.53
Weighted average common shares outstanding:
Basic (shares)	37,028	36,181
Diluted (shares)	37,973	37,034