Loans - Summary of Loans by Class Modified as Troubled Debt Restructurings (Detail) $ in Thousands  | 
12 Months Ended | 
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 Dec. 31, 2020  
USD ($)  
Loan 
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| Financing Receivable, Troubled Debt Restructuring [Line Items] | |
| Number of Loans | Loan | 5 | 
| Pre- Modification Outstanding Recorded Investment | $ 4,479 | 
| Post- Modification Outstanding Recorded Investment | $ 3,676 | 
| Real Estate | |
| Financing Receivable, Troubled Debt Restructuring [Line Items] | |
| Number of Loans | Loan | 5 | 
| Pre- Modification Outstanding Recorded Investment | $ 4,479 | 
| Post- Modification Outstanding Recorded Investment | $ 3,676 | 
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available. 
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- Definition Number of financing receivables that have been modified by troubled debt restructurings. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef 
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- Definition Amount, after troubled debt restructuring, of modified financing receivable. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef 
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- Definition Amount, before troubled debt restructuring, of financing receivable to be modified. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef 
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- Details 
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