Consolidated Statements Of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Consolidated Statements Of Income [Abstract]
Service revenues and sales	$ 589,233	$ 560,157
Cost of services provided and goods sold (excluding depreciation)	385,127	370,705
Selling, general and administrative expenses	115,873	100,095
Depreciation	13,287	12,286
Amortization	2,521	2,513
Other operating expense	92	1,739
Total costs and expenses	516,900	487,338
Income from operations	72,333	72,819
Interest expense	(425)	(1,551)
Other income/(expense) - net	12,577	(103)
Income before income taxes	84,485	71,165
Income taxes	(19,468)	(17,044)
Net income	$ 65,017	$ 54,121
Earnings Per Share:
Net income	$ 4.30	$ 3.62
Average number of shares outstanding	15,121	14,966
Diluted Earnings Per Share:
Net income	$ 4.24	$ 3.58
Average number of shares outstanding	15,339	15,110
Cash Dividends Per Share	$ 0.40	$ 0.38