CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Statement [Abstract]
Revenue	$ 302,780	$ 296,295
Direct costs	188,826	183,607
Operating costs and expenses:
Indirect and selling expenses	89,659	88,802
Depreciation and amortization	4,469	4,519
Amortization of intangible assets	2,244	2,734
Total operating costs and expenses	96,372	96,055
Operating income	17,582	16,633
Interest expense	(1,666)	(1,951)
Other income	104	109
Income before income taxes	16,020	14,791
Provision for income taxes	3,603	4,614
Net income	$ 12,417	$ 10,177
Earnings per Share:
Basic	$ 0.67	$ 0.54
Diluted	$ 0.65	$ 0.52
Weighted-average Shares:
Basic	18,670	18,972
Diluted	19,158	19,423
Other comprehensive income, net of tax	$ 1,609	$ 372
Comprehensive income, net of tax	$ 14,026	$ 10,549