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Acquisitions - Additional Information (Detail) - USD ($) $ in Thousands			12 Months Ended
	Jan. 31, 2019	Nov. 15, 2018	Dec. 31, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Total consideration transferred			$ 102,700	$ 94,200
Business acquisition, contingent cash consideration				18,000
Additional goodwill recognized			55,872	$ 39,664
Goodwill acquired during period net of assets acquired			48,700
Poten & Partners [Member]
Business Acquisition [Line Items]
Business acquisition date		Nov. 15, 2018
Ed Broking [Member]
Business Acquisition [Line Items]
Business acquisition date	Jan. 31, 2019
2019 Acquisitions [Member]
Business Acquisition [Line Items]
Measurement period adjustments			$ 7,100

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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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