CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
REVENUES
Revenue from Contract with Customer, Product and Service [Extensible Enumeration]	Customer Services [Member]	Customer Services [Member]	Customer Services [Member]	Customer Services [Member]
Customer services	$ 916,270	$ 840,427	$ 2,556,539	$ 2,319,192
COSTS AND EXPENSES
Cost of services provided (exclusive of depreciation and amortization below)	421,892	388,533	1,197,735	1,099,566
Sales, general and administrative	274,918	244,906	769,522	696,668
Restructuring costs	0	5,196	0	5,196
Depreciation and amortization	27,664	24,668	82,685	73,609
Total operating expenses	724,474	663,303	2,049,942	1,875,039
OPERATING INCOME	191,796	177,124	506,597	444,153
Interest expense, net	7,150	5,547	22,650	10,797
Other income, net	(582)	(493)	(933)	(6,226)
CONSOLIDATED INCOME BEFORE INCOME TAXES	185,228	172,070	484,880	439,582
PROVISION FOR INCOME TAXES	48,315	44,293	124,176	113,428
NET INCOME	$ 136,913	$ 127,777	$ 360,704	$ 326,154
NET INCOME PER SHARE - BASIC (in USD per share)	$ 0.28	$ 0.26	$ 0.74	$ 0.66
NET INCOME PER SHARE - DILUTED (in USD per share)	$ 0.28	$ 0.26	$ 0.74	$ 0.66
Weighted average shares outstanding - basic (in shares)	484,317	490,775	484,231	491,980
Weighted average shares outstanding - diluted (in shares)	484,359	490,965	484,270	492,158
DIVIDENDS PAID PER SHARE (in USD per share)	$ 0.15	$ 0.13	$ 0.45	$ 0.39