CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Statement [Abstract]
Revenue from Contract with Customer, Product and Service [Extensible List]	Service [Member]	Service [Member]	Service [Member]	Service [Member]
Revenue from services	$ 374,905	$ 193,968	$ 1,035,973	$ 620,811
Operating expenses:
Direct operating expenses	291,111	145,965	808,124	472,471
Selling, general and administrative expenses	52,847	40,804	149,518	128,939
Bad debt expense	1,441	946	2,411	2,383
Depreciation and amortization	2,680	3,247	7,132	10,472
Acquisition and integration-related costs	61	0	985	77
Restructuring costs	318	2,316	2,391	5,210
Impairment charges	0	1,071	2,070	16,082
Total operating expenses	348,458	194,349	972,631	635,634
Income (loss) from operations	26,447	(381)	63,342	(14,823)
Other expenses (income):
Interest expense	2,182	608	4,049	2,219
Other income, net	(375)	(10)	(616)	(46)
Income (loss) before income taxes	24,640	(979)	59,909	(16,996)
Income tax expense (benefit)	1,207	169	5,480	(32)
Consolidated net income (loss)	23,433	(1,148)	54,429	(16,964)
Less: Net income attributable to noncontrolling interest in subsidiary	0	186	0	610
Net income (loss) attributable to common shareholders	$ 23,433	$ (1,334)	$ 54,429	$ (17,574)
Net income (loss) per share attributable to common shareholders - Basic (in dollars per share)	$ 0.63	$ (0.04)	$ 1.49	$ (0.49)
Net income (loss) per share attributable to common shareholders - Diluted (in dollars per share)	$ 0.62	$ (0.04)	$ 1.46	$ (0.49)
Weighted average common shares outstanding:
Basic (shares)	36,963	36,176	36,593	36,058
Diluted (shares)	37,582	36,176	37,276	36,058