Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Revenues:
Total revenues	$ 1,018,891	$ 970,444
Costs and expenses:
Cost of services and product development	341,278	346,645
Selling, general and administrative	496,639	518,770
Depreciation	22,517	19,775
Amortization of intangibles	32,179	33,683
Acquisition and integration charges	1,560	2,772
Total costs and expenses	894,173	921,645
Operating income	124,718	48,799
Interest expense, net	(26,349)	(24,847)
Loss from divested operations	0	(2,075)
Other expense, net	(1,515)	(824)
Income before income taxes	96,854	21,053
Provision for income taxes	21,757	258
Net income	$ 75,097	$ 20,795
Net income per share:
Basic (in dollars per share)	$ 0.84	$ 0.23
Diluted (in dollars per share)	$ 0.83	$ 0.23
Weighted average shares outstanding:
Basic (in shares)	89,219	89,882
Diluted (in shares)	90,066	91,004
Research
Revenues:
Total revenues	$ 909,291	$ 825,374
Conferences
Revenues:
Total revenues	13,870	51,932
Consulting
Revenues:
Total revenues	$ 95,730	$ 93,138