Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies - Additional Information (Detail)

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Summary of Significant Accounting Policies - Additional Information (Detail)
 12 Months Ended
Jan. 01, 2020
USD ($)
Dec. 31, 2021
USD ($)
branch
Segment
shares
Dec. 31, 2020
USD ($)
Dec. 31, 2019
USD ($)
Jan. 24, 2019
shares
Financing Receivable, Recorded Investment, Past Due [Line Items]          
Number of reportable segments | Segment   1      
Accrued interest receivable on available-for-sale debt securities   $ 1,900,000 $ 1,200,000    
Increase to beginning balance of allowance for credit losses $ 17,400,000        
Decrease to beginning balance of allowance for off balance sheet items 335,000        
Retained earnings   196,784,000 114,621,000    
Impairment of intangible assets   0      
Goodwill impairment loss   0      
Bank-owned life insurance   $ 54,905,000 53,894,000    
Stock options, expiration term from date of grant   10 years      
Number of shares authorized for repurchase (percent)         5.00%
Number of shares authorized for repurchase under program (shares) | shares         1,500,000
Shares repurchased   $ 6,135,000 $ 2,196,000 $ 7,362,000  
Stock Repurchase Program          
Financing Receivable, Recorded Investment, Past Due [Line Items]          
Shares repurchased (shares) | shares   328,659      
Shares repurchased   $ 6,100,000      
Minimum          
Financing Receivable, Recorded Investment, Past Due [Line Items]          
Period of continuous service   3 years      
Maximum          
Financing Receivable, Recorded Investment, Past Due [Line Items]          
Period of continuous service   5 years      
Split Dollar Death Benefit Agreement          
Financing Receivable, Recorded Investment, Past Due [Line Items]          
Bank-owned life insurance   $ 3,000,000.0      
Cumulative Effect Period of Adoption Adjustment | Impact of ASU 2016-13 Adoption          
Financing Receivable, Recorded Investment, Past Due [Line Items]          
Retained earnings $ 12,200,000        
Full Service          
Financing Receivable, Recorded Investment, Past Due [Line Items]          
Number of branches | branch   35      
Loan Production          
Financing Receivable, Recorded Investment, Past Due [Line Items]          
Number of branches | branch   8