CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Income Statement [Abstract]
Service revenues	$ 1,351,907	$ 1,475,937
Costs of services	852,862	913,140
Gross margin	499,045	562,797
Selling, general and administrative expenses	460,163	521,899
Operating income	38,882	40,898
(Income) loss from investments held in employee deferred compensation trusts (which is completely offset by related costs and expenses - Note A)	20,171	(43,376)
Interest income, net	(3,572)	(6,413)
Income before income taxes	22,283	90,687
Provision for income taxes	4,933	26,986
Net income	$ 17,350	$ 63,701
Net income per share:
Basic (in usd per share)	$ 0.17	$ 0.61
Diluted (in usd per share)	$ 0.17	$ 0.61
Weighted average shares:
Basic (in shares)	100,666	103,787
Diluted (in shares)	101,015	104,399
Dividends declared per share (in usd per share)	$ 0.59	$ 0.53