CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Income Statement [Abstract]
Service revenues	$ 1,359,297	$ 1,354,477	$ 3,995,841	$ 4,076,127
Costs of services	827,202	850,246	2,509,810	2,563,377
Gross margin	532,095	504,231	1,486,031	1,512,750
Selling, general and administrative expenses	457,247	490,643	1,436,571	1,458,740
Operating income	74,848	13,588	49,460	54,010
(Income) loss from investments held in employee deferred compensation trusts (which is completely offset by related costs and expenses - Note A)	2,296	(47,621)	(90,355)	(85,104)
Interest income, net	(2,114)	(2,510)	(6,885)	(8,321)
Income before income taxes	74,666	63,719	146,700	147,435
Provision for income taxes	24,796	20,803	56,722	46,201
Net income	$ 49,870	$ 42,916	$ 89,978	$ 101,234
Net income per share:
Basic (in usd per share)	$ 0.50	$ 0.43	$ 0.90	$ 1.01
Diluted (in usd per share)	$ 0.49	$ 0.43	$ 0.90	$ 1.01
Weighted average shares:
Basic (in shares)	99,963	99,897	99,844	100,321
Diluted (in shares)	100,940	100,041	100,383	100,529
Dividends declared per share (in usd per share)	$ 0.59	$ 0.59	$ 1.77	$ 1.77