Acquisitions - Summary of Fair Value of Aggregate Consideration Paid (Detail) - SiriusDecisions, Inc [Member] $ in Thousands	Jan. 03, 2019 USD ($)
Business Acquisition [Line Items]
Cash paid at close	$ 246,801
Working capital adjustment	(1,259)
Total	$ 245,542

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

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