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
Income Statement [Abstract]
Revenue	$ 394,060	$ 360,315	$ 1,165,063	$ 1,072,540
Direct costs	254,175	223,288	732,903	677,311
Operating costs and expenses:
Indirect and selling expenses	99,940	100,123	316,100	302,649
Depreciation and amortization	4,665	5,143	14,663	15,386
Amortization of intangible assets	3,015	3,511	9,049	9,843
Total operating costs and expenses	107,620	108,777	339,812	327,878
Operating income	32,265	28,250	92,348	67,351
Interest expense	(2,550)	(3,488)	(7,845)	(10,921)
Other income (expense)	81	(223)	(382)	316
Income before income taxes	29,796	24,539	84,121	56,746
Provision for income taxes	9,406	6,668	25,068	14,607
Net income	$ 20,390	$ 17,871	$ 59,053	$ 42,139
Earnings per Share:
Basic	$ 1.08	$ 0.95	$ 3.13	$ 2.24
Diluted	$ 1.07	$ 0.94	$ 3.10	$ 2.20
Weighted-average Shares:
Basic	18,865	18,853	18,864	18,841
Diluted	19,061	19,086	19,077	19,111
Cash dividends declared per common share	$ 0.14	$ 0.14	$ 0.42	$ 0.42
Other comprehensive (loss) income, net of tax	$ (1,971)	$ 3,671	$ 1,241	$ (7,616)
Comprehensive income, net of tax	$ 18,419	$ 21,542	$ 60,294	$ 34,523