Consolidated Statements of Comprehensive Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Income Statement [Abstract]
Revenues	$ 462,766	$ 447,662
Operating costs and expenses:
Costs of services provided	386,932	379,691
Selling, general and administrative expense	41,997	44,966
Other income (expense):
Investment and other income, net	1,069	1,284
Interest expense	(365)	(395)
Income before taxes	34,541	23,894
Income tax provision	8,481	6,666
Net income	$ 26,060	$ 17,228
Per share data:
Basic income per common share (in dollars per share)	$ 0.37	$ 0.23
Diluted income per common share (in dollars per share)	$ 0.37	$ 0.23
Weighted average number of common shares outstanding:
Basic (in shares)	69,860	73,670
Diluted (in shares)	71,049	73,961
Comprehensive income:
Net income	$ 26,060	$ 17,228
Other comprehensive income
Unrealized (loss) gain on available-for-sale marketable securities, net of taxes	(387)	503
Total comprehensive income	$ 25,673	$ 17,731