UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Statement [Abstract]
Revenue	$ 338,861	$ 329,535	$ 665,599	$ 646,976
Direct costs	237,835	229,315	471,397	454,247
Gross profit	101,026	100,220	194,202	192,729
Selling, general and administrative expenses	78,017	76,901	157,830	155,698
Depreciation and amortization	1,542	1,692	3,192	3,443
Income from operations	21,467	21,627	33,180	33,588
Other expense, net	403	1,258	1,326	2,602
Income from continuing operations, before income taxes	21,064	20,369	31,854	30,986
Income tax expense	4,988	5,196	7,804	7,856
Income from continuing operations	16,076	15,173	24,050	23,130
Income from discontinued operations, net of tax	58,783	1,099	77,664	2,317
Net income	74,859	16,272	101,714	25,447
Other comprehensive (loss) income:
Change in fair value of interest rate swap, net of tax	(478)		(758)
Change in fair value of interest swap, net of tax		180		697
Comprehensive income	$ 74,381	$ 16,452	$ 100,956	$ 26,144
Earnings per share – basic:
Continuing operations (in dollars per share)	$ 0.67	$ 0.61	$ 0.99	$ 0.94
Discontinued operations (in dollars per share)	2.46	0.05	3.21	0.09
Earnings per share - basic (in dollars per share)	3.13	0.66	4.20	1.03
Earnings per share – diluted:
Continuing operations (in dollars per share)	0.66	0.60	0.97	0.92
Discontinued operations (in dollars per share)	2.40	0.05	3.14	0.09
Earnings per share – diluted (in dollars per share)	$ 3.06	$ 0.65	$ 4.11	$ 1.01
Weighted average shares outstanding – basic (in shares)	23,901	24,705	24,207	24,744
Weighted average shares outstanding – diluted (in shares)	24,458	25,178	24,745	25,142