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Acquisitions - Additional Information (Detail) - USD ($) $ in Millions			9 Months Ended	12 Months Ended
	Mar. 06, 2020	Jan. 31, 2019	Sep. 30, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Total consideration transferred			$ 9.6	$ 102.8
Goodwill acquired during period net of assets acquired			3.0	$ 48.7
Measurement period adjustments			$ (0.1)
Ed Broking [Member]
Business Acquisition [Line Items]
Business acquisition date		Jan. 31, 2019
Algomi Limited [Member]
Business Acquisition [Line Items]
Business acquisition date	Mar. 06, 2020

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Goodwill acquired during period net of measurement period adjustments.

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Date when the acquirer obtains control of the acquiree, in CCYY-MM-DD format.

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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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Amount of increase (decrease) from adjustments after acquisition date under purchase accounting of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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