Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Revenues:
Total revenues	$ 1,686,454	$ 1,595,060	$ 3,220,584	$ 3,067,986
Costs and expenses:
Cost of services and product development	531,731	513,314	1,006,761	972,755
Selling, general and administrative	776,888	712,071	1,507,196	1,401,904
Depreciation	30,535	27,594	59,401	53,911
Amortization of intangibles	20,204	22,940	42,098	45,930
Acquisition and integration charges	0	358	0	818
Total costs and expenses	1,359,358	1,276,277	2,615,456	2,475,318
Operating income	327,096	318,783	605,128	592,668
Interest expense, net	(11,801)	(19,990)	(25,214)	(39,209)
Other income, net	2,498	504	4,887	5,395
Income before income taxes	317,793	299,297	584,801	558,854
Provision for income taxes	77,010	69,749	133,079	118,761
Net income	$ 240,783	$ 229,548	$ 451,722	$ 440,093
Net income per share:
Basic (in dollars per share)	$ 3.12	$ 2.95	$ 5.85	$ 5.64
Diluted (in dollars per share)	$ 3.11	$ 2.93	$ 5.82	$ 5.60
Weighted average shares outstanding:
Basic (in shares)	77,157	77,816	77,257	78,078
Diluted (in shares)	77,359	78,288	77,606	78,651
Insights
Revenues:
Total revenues	$ 1,319,453	$ 1,265,992	$ 2,641,280	$ 2,534,164
Conferences
Revenues:
Total revenues	211,407	186,084	284,004	256,153
Consulting
Revenues:
Total revenues	$ 155,594	$ 142,984	$ 295,300	$ 277,669