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Goodwill and Other Intangible Assets - Additional Information (Detail) - USD ($)
3 Months Ended
Aug. 31, 2020
Mar. 31, 2021
Mar. 31, 2020
Goodwill [Line Items]      
Goodwill impairment $ 0    
Impairment charges   $ 0 $ 0
Amortization of other intangible assets   $ 3,075,000 $ 3,776,000
Core Deposits and Other Intangible Assets | Minimum      
Goodwill [Line Items]      
Estimated useful lives of core deposits and customer relationships   5 years  
Core Deposits and Other Intangible Assets | Maximum      
Goodwill [Line Items]      
Estimated useful lives of core deposits and customer relationships   15 years