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Business Combinations - Additional Information (Detail) - $ / shares
12 Months Ended
Dec. 15, 2019
Dec. 31, 2020
Business Acquisition [Line Items]    
Cash per share received by share holders $ 58.00  
Common stock shares received by shareholders 3.05  
Core Deposits [Member]    
Business Acquisition [Line Items]    
Amortized over an estimated useful life   10 years