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Allowance for Credit Losses and Credit Quality of Loans, Impairment Loans (Details) - USD ($) $ in Thousands | Dec. 31, 2020 | Dec. 31, 2019 | Sep. 30, 2019
--- | --- | --- | ---
Total Loans [Abstract] |  |  |
Recorded investment balance (book) |  | $ 18,253 |
Unpaid principal balance (legal) |  | 22,541 |
Related allowance |  | 0 |
Threshold balance for classified loans to be evaluated individually for impairment | $ 1,000 |  | $ 750
Originated Loans [Member] |  |  |
With no related allowance recorded [Abstract] |  |  |
Recorded investment balance (book) |  | 18,253 |
Unpaid principal balance (legal) |  | 22,541 |
Originated Loans [Member] | Commercial Loans [Member] |  |  |
With no related allowance recorded [Abstract] |  |  |
Recorded investment balance (book) |  | 3,488 |
Unpaid principal balance (legal) |  | 4,182 |
Originated Loans [Member] | Commercial Loans [Member] | C&I [Member] |  |  |
With no related allowance recorded [Abstract] |  |  |
Recorded investment balance (book) |  | 76 |
Unpaid principal balance (legal) |  | 302 |
Originated Loans [Member] | Commercial Loans [Member] | CRE [Member] |  |  |
With no related allowance recorded [Abstract] |  |  |
Recorded investment balance (book) |  | 2,410 |
Unpaid principal balance (legal) |  | 2,437 |
Originated Loans [Member] | Commercial Loans [Member] | Business Banking [Member] |  |  |
With no related allowance recorded [Abstract] |  |  |
Recorded investment balance (book) |  | 1,002 |
Unpaid principal balance (legal) |  | 1,443 |
Originated Loans [Member] | Consumer Loans [Member] |  |  |
With no related allowance recorded [Abstract] |  |  |
Recorded investment balance (book) |  | 7,044 |
Unpaid principal balance (legal) |  | 8,605 |
Originated Loans [Member] | Consumer Loans [Member] | Indirect Auto [Member] |  |  |
With no related allowance recorded [Abstract] |  |  |
Recorded investment balance (book) |  | 154 |
Unpaid principal balance (legal) |  | 242 |
Originated Loans [Member] | Consumer Loans [Member] | Direct [Member] |  |  |
With no related allowance recorded [Abstract] |  |  |
Recorded investment balance (book) |  | 6,862 |
Unpaid principal balance (legal) |  | 8,335 |
Originated Loans [Member] | Consumer Loans [Member] | Specialty Lending [Member] |  |  |
With no related allowance recorded [Abstract] |  |  |
Recorded investment balance (book) |  | 28 |
Unpaid principal balance (legal) |  | 28 |
Originated Loans [Member] | Residential Real Estate [Member] |  |  |
With no related allowance recorded [Abstract] |  |  |
Recorded investment balance (book) |  | 7,721 |
Unpaid principal balance (legal) |  | $ 9,754 |

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