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Goodwill and Intangible Assets - Narrative (Detail) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]      
Amortization expense $ 22.1 $ 22.3 $ 22.3