Unaudited Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income Statement [Abstract]
Service revenue, net	$ 282,256	$ 363,911	$ 649,547	$ 731,726
Operating expenses:
Service expense	196,106	345,948	528,767	686,446
General and administrative expense	31,199	16,860	51,994	36,262
Depreciation and amortization	6,108	4,353	9,898	8,827
Total operating expenses	233,413	367,161	590,659	731,535
Operating income (loss)	48,843	(3,250)	58,888	191
Other expenses (income):
Interest expense, net	1,498	301	1,739	604
Other income	0	(66)	0	(132)
Equity in net (gain) loss of investee	(4,425)	1,315	(1,875)	2,971
Income (loss) from continuing operations before income taxes	51,770	(4,800)	59,024	(3,252)
Provision (benefit) for income taxes	14,471	(1,391)	5,425	(1,157)
Income (loss) from continuing operations, net of tax	37,299	(3,409)	53,599	(2,095)
(Loss) income from discontinued operations, net of tax	(301)	1,697	(503)	966
Net income (loss)	36,998	(1,712)	53,096	(1,129)
Net (loss) income available to common stockholders (Note 11)	$ (12,819)	$ (2,810)	$ 1,920	$ (3,314)
Basic (loss) earnings per common share:
Continuing operations (in dollars per share)	$ (0.96)	$ (0.35)	$ 0.19	$ (0.33)
Discontinued operations (in dollars per share)	(0.02)	0.13	(0.04)	0.07
Basic loss per common share (in dollars per share)	(0.98)	(0.22)	0.15	(0.26)
Diluted (loss) earnings per common share:
Continuing operations (in dollars per share)	(0.96)	(0.35)	0.19	(0.33)
Discontinued operations (in dollars per share)	(0.02)	0.13	(0.04)	0.07
Diluted earnings per common share (in dollars per share)	$ (0.98)	$ (0.22)	$ 0.15	$ (0.26)
Weighted-average number of common shares outstanding:
Basic (in shares)	13,077,596	12,973,496	13,032,931	12,937,054
Diluted (in shares)	13,077,596	12,973,496	13,059,699	12,937,054