CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Revenue	$ 360,315	$ 373,918	$ 1,072,540	$ 1,081,889
Direct costs	223,288	238,158	677,311	689,160
Operating costs and expenses:
Indirect and selling expenses	100,123	100,130	302,649	298,099
Depreciation and amortization	5,143	5,035	15,386	15,392
Amortization of intangible assets	3,511	1,931	9,843	6,143
Total operating costs and expenses	108,777	107,096	327,878	319,634
Operating income	28,250	28,664	67,351	73,095
Interest expense	(3,488)	(2,824)	(10,921)	(8,211)
Other (expense) income	(223)	(141)	316	(367)
Income before income taxes	24,539	25,699	56,746	64,517
Provision for income taxes	6,668	6,069	14,607	14,958
Net income	$ 17,871	$ 19,630	$ 42,139	$ 49,559
Earnings per Share:
Basic	$ 0.95	$ 1.04	$ 2.24	$ 2.63
Diluted	$ 0.94	$ 1.02	$ 2.20	$ 2.58
Weighted-average Shares:
Basic	18,853	18,799	18,841	18,810
Diluted	19,086	19,169	19,111	19,208
Cash dividends declared per common share	$ 0.14	$ 0.14	$ 0.42	$ 0.42
Other comprehensive income (loss), net of tax	$ 3,671	$ (3,281)	$ (7,616)	$ (5,851)
Comprehensive income, net of tax	$ 21,542	$ 16,349	$ 34,523	$ 43,708