Consolidated Statements of Comprehensive Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Statement [Abstract]
Revenue	$ 1,963,238	$ 1,779,964	$ 1,553,048
Direct costs	1,265,018	1,134,422	979,570
Operating costs and expenses:
Indirect and selling expenses	505,162	486,863	430,572
Depreciation and amortization	25,277	21,482	19,478
Amortization of intangible assets	35,461	28,435	12,492
Total operating costs and expenses	565,900	536,780	462,542
Operating income	132,320	108,762	110,936
Interest, net	(39,681)	(23,281)	(9,984)
Other income (expense)	3,908	(1,501)	(862)
Income before income taxes	96,547	83,980	100,090
Provision for income taxes	13,935	19,737	28,958
Net income	$ 82,612	$ 64,243	$ 71,132
Earnings per share:
Basic	$ 4.39	$ 3.41	$ 3.77
Diluted	$ 4.35	$ 3.38	$ 3.72
Weighted-average common shares outstanding:
Basic	18,802	18,818	18,868
Diluted	18,994	19,033	19,124
Cash dividends declared per common share	$ 0.56	$ 0.56	$ 0.56
Other comprehensive (loss) income, net of tax	$ (3,752)	$ 2,902	$ 3,071
Comprehensive income, net of tax	$ 78,860	$ 67,145	$ 74,203