Goodwill and Other Intangible Assets - Additional Information (Detail) - USD ($)		12 Months Ended
	Jan. 01, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Finite Lived Intangible Assets [Line Items]
Goodwill impairment charges	$ 0	$ 0	$ 0	$ 0
Measurement period adjustments related to deferred taxes		800,000
Accumulated goodwill impairment losses		0
Amortization of intangible assets		22,619,000	1,162,000	$ 781,000
SiriusDecisions, Inc [Member]
Finite Lived Intangible Assets [Line Items]
Intangible assets acquired		115,000,000
Amortization of intangible assets		$ 21,800,000
FeedbackNow [Member]
Finite Lived Intangible Assets [Line Items]
Intangible assets acquired			4,800,000
SocialGlimpz Inc. [Member]
Finite Lived Intangible Assets [Line Items]
Intangible assets acquired			$ 600,000
Maximum [Member]
Finite Lived Intangible Assets [Line Items]
Goodwill measurement period		1 year