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Investment Securities - Additional Information (Detail)
3 Months Ended
Mar. 31, 2024
USD ($)
investmentSecurity
securityLoan
Mar. 31, 2023
USD ($)
Dec. 31, 2023
USD ($)
Investment Securities [Line Items]      
Proceeds from the sale of investment securities $ 0 $ 24,200,000  
Gross realized losses from the sale of investment securities   $ 200,000  
Securities pledged as collateral 741,500,000   $ 702,200,000
Residential real estate mortgage-backed securities $ 1,300,000,000    
Life of mortgage-backed securities 7 years 3 months    
Allowance for credit losses $ 0   0
Obligations of U.S. government agencies      
Investment Securities [Line Items]      
Impairment losses recognized 0    
Allowance for credit losses $ 0   0
Number of available for sale securities in unrealized loss position (in investment securities) | investmentSecurity 168    
Percentage of aggregate depreciation in unrealized losses 13.29%    
Obligations of states and political subdivisions      
Investment Securities [Line Items]      
Impairment losses recognized $ 0    
Allowance for credit losses $ 0   0
Number of available for sale securities in unrealized loss position (in investment securities) | investmentSecurity 157    
Percentage of aggregate depreciation in unrealized losses 11.25%    
Corporate bonds      
Investment Securities [Line Items]      
Impairment losses recognized $ 0    
Allowance for credit losses $ 0   0
Number of available for sale securities in unrealized loss position (in investment securities) | investmentSecurity 6    
Percentage of aggregate depreciation in unrealized losses 6.95%    
Asset backed securities      
Investment Securities [Line Items]      
Impairment losses recognized $ 0    
Allowance for credit losses $ 0   0
Number of available for sale securities in unrealized loss position (in investment securities) | investmentSecurity 29    
Percentage of aggregate depreciation in unrealized losses 1.56%    
Non-agency collateralized mortgage obligations      
Investment Securities [Line Items]      
Impairment losses recognized $ 0    
Allowance for credit losses $ 0   $ 0
Number of available for sale securities in unrealized loss position (in investment securities) | securityLoan 22    
Allowance for credit loss $ 0    
Percentage of aggregate depreciation in unrealized losses 10.59%