Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Revenues:
Total revenues	$ 1,331,868	$ 1,156,282	$ 3,971,129	$ 3,427,639
Costs and expenses:
Cost of services and product development	416,837	359,237	1,218,405	1,044,506
Selling, general and administrative	613,031	512,573	1,835,846	1,488,324
Depreciation	22,882	25,371	68,993	76,972
Amortization of intangibles	24,369	27,109	74,271	83,777
Acquisition and integration charges	1,331	1,771	5,827	3,713
Total costs and expenses	1,078,450	926,061	3,203,342	2,697,292
Operating income	253,418	230,221	767,787	730,347
Interest expense, net	(30,286)	(31,599)	(91,399)	(85,138)
Gain on event cancellation insurance claims	0	0	0	135,545
Other income, net	8,930	211	46,684	12,019
Income before income taxes	232,062	198,833	723,072	792,773
Provision for income taxes	58,517	49,968	172,087	208,572
Net income	$ 173,545	$ 148,865	$ 550,985	$ 584,201
Net income per share:
Basic (in dollars per share)	$ 2.19	$ 1.78	$ 6.84	$ 6.80
Diluted (in dollars per share)	$ 2.17	$ 1.76	$ 6.77	$ 6.72
Weighted average shares outstanding:
Basic (in shares)	79,259	83,566	80,516	85,877
Diluted (in shares)	80,059	84,766	81,373	86,925
Research
Revenues:
Total revenues	$ 1,147,823	$ 1,037,124	$ 3,426,532	$ 3,020,094
Conferences
Revenues:
Total revenues	77,031	24,415	200,910	107,396
Consulting
Revenues:
Total revenues	$ 107,014	$ 94,743	$ 343,687	$ 300,149