Goodwill and Intangible Assets (Tables)

3 Months Ended

Mar. 31, 2016

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of changes to the carrying amount of goodwill by reporting unit

The following table presents changes to the carrying amount of goodwill by reportable segment during the three months ended March 31, 2016 (in thousands):

	Research		Consulting			Events		Total
Balance, December 31, 2015 (1)	$	575,292	$	98,412		$	41,655	$	715,359
Additions due to acquisitions (2)	1,913		—			—		1,913
Foreign currency translation adjustments	1,161		(427		)	28		762
Balance, March 31, 2016	$	578,366	$	97,985		$	41,683	$	718,034

(1) The Company does not have any accumulated goodwill impairment losses.

(2) The additions to goodwill reflect certain measurement period working capital and other adjustments related to the acquisition of Capterra, Inc. in September 2015.

Schedule of amortizable intangible assets

The following tables present reconciliations of the carrying amounts of amortizable intangible assets as of the dates indicated (in thousands):

March 31, 2016	Trade Name			Customer Relationships			Content			Software			Non-Compete			Total
Gross cost, December 31, 2015	$	4,144		$	62,860		$	5,450		$	16,219		$	29,330		$	118,003
Foreign currency translation impact and other	18			204			(150		)	(85		)	17			4
Gross cost	4,162			63,064			5,300			16,134			29,347			118,007
Accumulated amortization (1), (2)	(946		)	(11,675		)	(3,868		)	(4,926		)	(6,039		)	(27,454		)
Balance, March 31, 2016	$	3,216		$	51,389		$	1,432		$	11,208		$	23,308		$	90,553

December 31, 2015	Trade Name			Customer Relationships			Content			Software			Non-Compete			Total
Gross cost	$	4,144		$	62,860		$	5,450		$	16,219		$	29,330		$	118,003
Accumulated amortization (1), (2)	(681		)	(9,028		)	(3,525		)	(3,699		)	(4,526		)	(21,459		)
Balance, December 31, 2015	$	3,463		$	53,832		$	1,925		$	12,520		$	24,804		$	96,544

(1) Intangible assets are being amortized against earnings over the following periods: Trade name—2 to 4 years; Customer relationships—4 to 7 years; Content—1.5 to 4 years; Software—3 years; Non-compete—3 to 5 years.

(2) Aggregate amortization expense related to intangible assets was $6.2 million and $2.1 million for the three months ended March 31, 2016 and 2015, respectively.

Schedule of estimated future amortization expense by year

The estimated future amortization expense by year from amortizable intangibles is as follows (in thousands):

2016 (remaining nine months)	$	17,938
2017	21,516
2018	18,855
2019	14,346
2020	12,472
Thereafter	5,426
	$	90,553