Consolidated Statements of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues:
Research services	$ 207,517	$ 202,843	$ 203,091
Advisory services and events	104,545	94,807	89,940
Total revenues	312,062	297,650	293,031
Operating expenses:
Cost of services and fulfillment	126,199	117,061	111,228
Selling and marketing	115,753	107,073	101,390
General and administrative	38,584	38,280	36,866
Depreciation	9,325	9,268	8,921
Amortization of intangible assets	2,171	2,230	2,445
Reorganization costs	1,817	1,905	1,421
Total operating expenses	293,849	275,817	262,271
Income from operations	18,213	21,833	30,760
Other income, net	464	592	1,300
Gains (losses) on investments, net	(288)	(2,433)	94
Income before income taxes	18,389	19,992	32,154
Income tax provision	7,524	6,968	5,858
Net income	$ 10,865	$ 13,024	$ 26,296
Basic income per common share	$ 0.58	$ 0.62	$ 1.17
Diluted income per common share	$ 0.57	$ 0.61	$ 1.15
Basic weighted average common shares outstanding	18,713	20,861	22,500
Diluted weighted average common shares outstanding	19,007	21,353	22,929