Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement of Comprehensive Income [Abstract]
Revenue	$ 282,719	$ 238,389	$ 862,097	$ 752,787
Operating expenses	238,328	204,760	699,233	613,603
Gross margin	44,391	33,629	162,864	139,184
Corporate general and administrative expenses	13,035	11,339	41,334	32,988
Legal settlement, net	0	0	30,468	0
Operating income	31,356	22,290	91,062	106,196
Other income (expense):
Interest expense	(1,016)	(974)	(2,852)	(4,167)
Gain (loss) on sale of operations, net	0	(74)	6,385	78
Other (expense) income, net	(1,133)	5,914	12,029	3,450
Total other (expense) income, net	(2,149)	4,866	15,562	(639)
Income from continuing operations before income tax    expense	29,207	27,156	106,624	105,557
Income tax expense	7,512	7,060	26,100	27,120
Income from continuing operations	21,695	20,096	80,524	78,437
Loss from discontinued operations, net of tax	(4)	(19)	(17)	(44)
Net income	$ 21,691	$ 20,077	$ 80,507	$ 78,393
Basic:
Continuing operations (in dollars per share)	$ 0.41	$ 0.37	$ 1.52	$ 1.44
Discontinued operations (in dollars per share)	0	0	0	0
Net income (in dollars per share)	0.41	0.37	1.52	1.44
Diluted:
Continuing operations (in dollars per share)	0.41	0.36	1.50	1.41
Discontinued operations (in dollars per share)	0	0	0	0
Net income (in dollars per share)	$ 0.41	$ 0.36	$ 1.50	$ 1.41
Basic weighted average shares outstanding (in shares)	52,425	54,403	52,885	54,372
Diluted weighted average shares outstanding (in shares)	53,226	55,360	53,796	55,473
Comprehensive income:
Net income	$ 21,691	$ 20,077	$ 80,507	$ 78,393
Other comprehensive income (loss), net of tax	159	(186)	1,071	(1,815)
Comprehensive income	$ 21,850	$ 19,891	$ 81,578	$ 76,578