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Goodwill and Intangible Assets - Additional Information (Detail) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2021
Sep. 30, 2020
Sep. 30, 2021
Sep. 30, 2020
Dec. 31, 2020
Finite-Lived Intangible Liabilities [Line Items]          
Amortization expense $ 5.7 $ 4.0 $ 16.1 $ 11.8  
Impairment of intangible assets     $ 0.0   $ 0.0