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Securities - Additional Information (Detail) - USD ($)
1 Months Ended 9 Months Ended
Mar. 31, 2022
Sep. 30, 2022
Sep. 30, 2021
Aug. 25, 2022
Jan. 10, 2022
Debt Securities, Available-for-Sale [Line Items]          
Sale of low yielding securities $ 226,000,000        
Debt securities. average yield percentage 0.16%        
Reinvested in debt securities $ 220,000,000        
Reinvested debt securities, average yield percentage 1.86%        
Proceeds from sales of available for sale securities   $ 222,474,000 $ 0    
Avaliable for sale of debt securities realized gains or losses     $ 0    
United States Treasury Notes [Member]          
Debt Securities, Available-for-Sale [Line Items]          
Debt securities purchased at par value       $ 300,000,000 $ 600,000,000
Debt securities. average yield percentage       3.27% 1.42%
Debt securities, average maturity term       58 months 53 months