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Loans and Allowance for Credit Losses - Summary of charge-offs (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2023 | Sep. 30, 2022 | Sep. 30, 2023 | Sep. 30, 2022
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Write-off, by Origination Year [Abstract] |  |  |  |
Current period gross charge-off, 2023 |  |  | $ 39 |
Current period gross charge-off, 2022 |  |  | 2 |
Current period gross charge-off, 2021 |  |  | 37 |
Current period gross charge-off, 2020 |  |  | 38 |
Current period gross charge-off, 2019 |  |  | 251 |
Current period gross charge-off, Prior |  |  | 149 |
Current period gross charge-off, Total | $ 151 | $ 747 | 516 | $ 1,466
Commercial |  |  |  |
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Write-off, by Origination Year [Abstract] |  |  |  |
Current period gross charge-off, 2023 |  |  | 39 |
Current period gross charge-off, 2021 |  |  | 28 |
Current period gross charge-off, 2020 |  |  | 11 |
Current period gross charge-off, 2019 |  |  | 247 |
Current period gross charge-off, Prior |  |  | 69 |
Current period gross charge-off, Total | 134 | 672 | 394 | 1,336
Commercial | Commercial and industrial |  |  |  |
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Write-off, by Origination Year [Abstract] |  |  |  |
Current period gross charge-off, 2023 |  |  | 39 |
Current period gross charge-off, 2021 |  |  | 28 |
Current period gross charge-off, 2020 |  |  | 11 |
Current period gross charge-off, 2019 |  |  | 247 |
Current period gross charge-off, Prior |  |  | 69 |
Current period gross charge-off, Total | 134 | 672 | 394 | 1,336
Consumer |  |  |  |
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Write-off, by Origination Year [Abstract] |  |  |  |
Current period gross charge-off, 2022 |  |  | 2 |
Current period gross charge-off, 2021 |  |  | 9 |
Current period gross charge-off, 2020 |  |  | 27 |
Current period gross charge-off, 2019 |  |  | 4 |
Current period gross charge-off, Prior |  |  | 80 |
Current period gross charge-off, Total | 17 | 75 | 122 | 130
Consumer | Other revolving and installment |  |  |  |
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Write-off, by Origination Year [Abstract] |  |  |  |
Current period gross charge-off, 2022 |  |  | 2 |
Current period gross charge-off, 2020 |  |  | 27 |
Current period gross charge-off, 2019 |  |  | 4 |
Current period gross charge-off, Prior |  |  | 3 |
Current period gross charge-off, Total | 8 | $ 75 | 36 | $ 130
Consumer | Real estate first mortgage |  |  |  |
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Write-off, by Origination Year [Abstract] |  |  |  |
Current period gross charge-off, 2021 |  |  | 9 |
Current period gross charge-off, Total |  |  | 9 |
Consumer | Real estate first mortgage | Residential |  |  |  |
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Write-off, by Origination Year [Abstract] |  |  |  |
Current period gross charge-off, Total | $ 9 |  | 9 |
Consumer | Real estate junior lien |  |  |  |
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Write-off, by Origination Year [Abstract] |  |  |  |
Current period gross charge-off, Prior |  |  | 77 |
Current period gross charge-off, Total |  |  | 77 |
Consumer | Real estate junior lien | Residential |  |  |  |
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Write-off, by Origination Year [Abstract] |  |  |  |
Current period gross charge-off, Total |  |  | $ 77 |

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