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Property and Equipment - Additional Information (Detail) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Property, Plant and Equipment [Line Items]      
Depreciation and amortization $ 15.0 $ 12.9 $ 9.4
Accumulated depreciation 3.4 3.1  
Leasehold Improvements [Member]      
Property, Plant and Equipment [Line Items]      
Capitalized asset retirement costs $ 3.3 $ 1.3