CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
REVENUES
Revenue	$ 3,761,050	$ 3,388,708	$ 3,073,278
Revenue from contract with customer, product and service	Customer Services [Member]	Customer Services [Member]	Customer Services [Member]
COSTS AND EXPENSES
Cost of services provided (exclusive of depreciation and amortization below)	$ 1,777,006	$ 1,603,197	$ 1,469,871
Sales, general and administrative	1,133,232	1,015,067	915,233
Restructuring costs	0	0	5,196
Depreciation and amortization	124,744	113,220	99,752
Total operating expenses	3,034,982	2,731,484	2,490,052
OPERATING INCOME	726,068	657,224	583,226
Interest expense, net	28,558	27,677	19,055
Other (income) expense, net	(3,416)	(683)	(22,086)
CONSOLIDATED INCOME BEFORE INCOME TAXES	700,926	630,230	586,257
PROVISION FOR INCOME TAXES	174,221	163,851	151,300
NET INCOME	$ 526,705	$ 466,379	$ 434,957
NET INCOME PER SHARE - BASIC (in USD per share)	$ 1.09	$ 0.96	$ 0.89
NET INCOME PER SHARE - DILUTED (in USD per share)	$ 1.09	$ 0.96	$ 0.89
Weighted average shares outstanding - basic (in shares)	484,105	484,249	489,949
Weighted average shares outstanding - diluted (in shares)	484,147	484,295	490,130
DIVIDENDS PAID PER SHARE (in USD per share)	$ 0.6775	$ 0.6150	$ 0.5400