Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Revenues:
Research	$ 504,652	$ 440,271
Consulting	85,248	84,940
Events	35,269	32,055
Total revenues	625,169	557,266
Costs and expenses:
Cost of services and product development	237,609	212,041
Selling, general and administrative	304,244	257,411
Depreciation	10,240	8,834
Amortization of intangibles	6,290	6,183
Acquisition and integration charges	13,272	8,368
Total costs and expenses	571,655	492,837
Operating income	53,514	64,429
Interest expense, net	(5,906)	(6,006)
Other income, net	889	1,884
Income before income taxes	48,497	60,307
Provision for income taxes	12,064	15,320
Net income	$ 36,433	$ 44,987
Net income per share:
Basic (in dollars per share)	$ 0.44	$ 0.55
Diluted (in dollars per share)	$ 0.43	$ 0.54
Weighted average shares outstanding:
Basic (in shares)	82,835	82,451
Diluted (in shares)	84,095	83,464