Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Revenues:
Research	$ 763,924	$ 511,306
Events	46,087	35,269
Consulting	82,896	78,594
Talent Assessment & Other	70,658	0
Total revenues	963,565	625,169
Costs and expenses:
Cost of services and product development	357,209	237,609
Selling, general and administrative	487,745	304,244
Depreciation	16,410	10,240
Amortization of intangibles	51,646	6,290
Acquisition and integration charges	59,266	13,272
Total costs and expenses	972,276	571,655
Operating (loss) income	(8,711)	53,514
Interest expense, net	(35,059)	(5,906)
Other income, net	899	889
(Loss) income before income taxes	(42,871)	48,497
(Benefit) provision for income taxes	(23,284)	12,064
Net (loss) income	$ (19,587)	$ 36,433
Net (loss) income per share:
Basic (in dollars per share)	$ (0.22)	$ 0.44
Diluted (in dollars per share)	$ (0.22)	$ 0.43
Weighted average shares outstanding:
Basic (in shares)	91,005	82,835
Diluted (in shares)	91,005	84,095