Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Revenues:
Total revenues	$ 1,376,521	$ 1,167,319	$ 2,639,261	$ 2,271,357
Costs and expenses:
Cost of services and product development	424,535	350,802	801,568	685,269
Selling, general and administrative	604,911	488,496	1,222,815	975,751
Depreciation	22,910	25,851	46,111	51,601
Amortization of intangibles	24,754	26,154	49,902	56,668
Acquisition and integration charges	2,289	1,302	4,496	1,942
Total costs and expenses	1,079,399	892,605	2,124,892	1,771,231
Operating income	297,122	274,714	514,369	500,126
Interest expense, net	(29,719)	(27,390)	(61,113)	(53,539)
Gain on event cancellation insurance claims	0	135,545	0	135,545
Other income (expense), net	8,548	(3,682)	37,754	11,808
Income before income taxes	275,951	379,187	491,010	593,940
Provision for income taxes	71,026	107,951	113,570	158,604
Net income	$ 204,925	$ 271,236	$ 377,440	$ 435,336
Net income per share:
Basic (in dollars per share)	$ 2.55	$ 3.16	$ 4.65	$ 5.00
Diluted (in dollars per share)	$ 2.53	$ 3.13	$ 4.60	$ 4.95
Weighted average shares outstanding:
Basic (in shares)	80,271	85,712	81,145	87,032
Diluted (in shares)	80,974	86,589	82,011	87,921
Research
Revenues:
Total revenues	$ 1,142,329	$ 1,003,238	$ 2,278,709	$ 1,982,970
Conferences
Revenues:
Total revenues	113,525	58,179	123,879	82,981
Consulting
Revenues:
Total revenues	$ 120,667	$ 105,902	$ 236,673	$ 205,406