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Financial Instruments with Off-Balance Sheet Risk (Details) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Dec. 31, 2020 | Dec. 31, 2021 | Dec. 31, 2020 | Sep. 30, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |
Increase (decrease) in available commitments |  | $ (993) |  |
Commercial lines of credit |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |
Loan commitments and standby letters of credit, off-balance sheet | $ 297,898 | 330,234 | $ 297,898 |
Revolving home equity lines |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |
Loan commitments and standby letters of credit, off-balance sheet | 191,969 | 210,938 | 191,969 |
Undisbursed construction loans |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |
Loan commitments and standby letters of credit, off-balance sheet | 101,307 | 78,381 | 101,307 |
Personal and other lines of credit |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |
Loan commitments and standby letters of credit, off-balance sheet | 10,611 | 11,001 | 10,611 |
Standby letters of credit |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |
Loan commitments and standby letters of credit, off-balance sheet | 2,657 | 3,657 | 2,657 |
Total unfunded loan commitments and standby letters of credit |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |
Loan commitments and standby letters of credit, off-balance sheet | 604,442 | 634,211 | $ 604,442 |
Percentage of commitments expiring in 2021 |  |  | 39.00% |
Percentage of commitments expiring between 2023 and 2029 |  |  | 49.00% |
Percentage of commitments expiring 2029 and thereafter |  |  | 12.00% |
Allowance for off-balance sheet commitments | 2,800 | $ 1,800 | $ 2,800 | $ 610
Increase (decrease) in available commitments | 36,900 |  |  |
Total unfunded loan commitments and standby letters of credit | Cumulative Effect, Period of Adoption, Adjusted Balance |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |
Allowance for off-balance sheet commitments | 1,100 |  | 1,100 |
Total unfunded loan commitments and standby letters of credit | Cumulative Effect, Period of Adoption, Adjustment |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |
Allowance for off-balance sheet commitments | $ 550 |  | $ 550 |

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