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Note 5 - Loans and Related Allowance for Loan and Lease Losses (Details Textual) | 3 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 31, 2020 USD ($) | Sep. 30, 2020 USD ($) | Jun. 30, 2020 USD ($) | Mar. 31, 2020 USD ($) | Dec. 31, 2019 USD ($) | Sep. 30, 2019 USD ($) | Jun. 30, 2019 USD ($) | Mar. 31, 2019 USD ($) | Dec. 31, 2020 USD ($) | Dec. 31, 2019 USD ($)
Loans and Leases Receivable, Net of Deferred Income, Total | $ 1,104,085,000 |  |  |  | $ 984,258,000 |  |  |  | $ 1,104,085,000 | $ 984,258,000
Loans and Leases Receivable, Deferred Income, Total | 4,400,000 |  |  |  | 1,300,000 |  |  |  | 4,400,000 | 1,300,000
Financing Receivable, Troubled Debt Restructuring | 2,900,000 |  |  |  | 3,600,000 |  |  |  | 2,900,000 | 3,600,000
Financing Receivable, Allowance for Credit Loss, Writeoff |  |  |  |  |  |  |  |  | $ 45,000 | 33,000
Financing Receivable, Troubled Debt Restructuring, Subsequent Default |  |  |  |  |  |  |  |  |  | $ 36,000
Financing Receivable, Troubled Debt Restructuring, Subsequent Default, Number of Contracts |  |  |  |  |  |  |  |  | 0 | 0
Number of Days Past Due (Day) |  |  |  |  |  |  |  |  | 90 days |
Loans and Leases Receivable, Impaired, Interest Lost on Nonaccrual Loans |  |  |  |  |  |  |  |  | $ 126,000 | $ 377,000
Allowance for Loan and Lease Losses, Write-offs |  |  |  |  |  |  |  |  | 3,839,000 | 1,809,000
Provision for Loan and Lease Losses, Total | 2,100,000 | $ 4,000,000 | $ 1,000,000 | $ 2,740,000 | 460,000 | $ 80,000 | $ 110,000 | $ 240,000 | 9,840,000 | 890,000
Threshold For Loans Evaluated For Impairment [Member] |  |  |  |  |  |  |  |  |  |
Loans and Leases Receivable, before Fees, Gross | 500,000 |  |  |  |  |  |  |  | 500,000 |
Threshold For Loans Evaluated For Impairment [Member] | Outside Consultant [Member] |  |  |  |  |  |  |  |  |  |
Loans and Leases Receivable, before Fees, Gross | 250,000 |  |  |  |  |  |  |  | 250,000 |
Threshold For Loans Evaluated For Impairment [Member] | Criticized Relationships [Member] |  |  |  |  |  |  |  |  |  |
Financing Receivable, before Allowance for Credit Loss, Total | 125,000 |  |  |  |  |  |  |  | 125,000 |
Commercial And Industrial [Member] |  |  |  |  |  |  |  |  |  |
Loans and Leases Receivable, Net of Deferred Income, Total | 232,044,000 |  |  |  | 89,527,000 |  |  |  | 232,044,000 | 89,527,000
Allowance for Loan and Lease Losses, Write-offs |  |  |  |  |  |  |  |  | 245,000 | 519,000
Provision for Loan and Lease Losses, Total |  |  |  |  |  |  |  |  | 848,000 | (76,000)
Commercial And Industrial [Member] | Provision Fluctuation [Member] |  |  |  |  |  |  |  |  |  |
Allowance for Loan and Lease Losses, Write-offs |  |  |  |  |  |  |  |  | 245,000 | 438,000
Commercial Real Estate Portfolio Segment [Member] | Provision Fluctuation [Member] |  |  |  |  |  |  |  |  |  |
Allowance for Loan and Lease Losses, Write-offs |  |  |  |  |  |  |  |  | 3,000,000.0 |
Residential Portfolio Segment [Member] |  |  |  |  |  |  |  |  |  |
Loans and Leases Receivable, Net of Deferred Income, Total | 233,995,000 |  |  |  | 234,798,000 |  |  |  | 233,995,000 | 234,798,000
Allowance for Loan and Lease Losses, Write-offs |  |  |  |  |  |  |  |  | 62,000 | 361,000
Provision for Loan and Lease Losses, Total |  |  |  |  |  |  |  |  | 977,000 | 280,000
Residential Portfolio Segment [Member] | Provision Fluctuation [Member] |  |  |  |  |  |  |  |  |  |
Allowance for Loan and Lease Losses, Write-offs |  |  |  |  |  |  |  |  | 62,000 | 360,000
Consumer Portfolio Segment [Member] |  |  |  |  |  |  |  |  |  |
Loans and Leases Receivable, Net of Deferred Income, Total | 9,823,000 |  |  |  | $ 14,411,000 |  |  |  | 9,823,000 | 14,411,000
Allowance for Loan and Lease Losses, Write-offs |  |  |  |  |  |  |  |  | 405,000 | 735,000
Provision for Loan and Lease Losses, Total |  |  |  |  |  |  |  |  | 375,000 | 628,000
Consumer Portfolio Segment [Member] | Provision Fluctuation [Member] |  |  |  |  |  |  |  |  |  |
Allowance for Loan and Lease Losses, Write-offs |  |  |  |  |  |  |  |  | 383,000 | $ 566,000
Small Business Administration (SBA), CARES Act, Paycheck Protection Program [Member] |  |  |  |  |  |  |  |  |  |
Loans and Leases Receivable, Deferred Income, Total | 2,700,000 |  |  |  |  |  |  |  | 2,700,000 |
Small Business Administration (SBA), CARES Act, Paycheck Protection Program [Member] | Commercial And Industrial [Member] |  |  |  |  |  |  |  |  |  |
Loans and Leases Receivable, Net of Deferred Income, Total | $ 116,100,000 |  |  |  |  |  |  |  | $ 116,100,000 |
Financing Receivable, Allowance for Credit Losses, Percentage of Portfolio | 0.40% |  |  |  |  |  |  |  | 0.40% |
Financing Receivable, Allowance for Credit Loss, Ending Balance | $ 464,000 |  |  |  |  |  |  |  | $ 464,000 |
Provision for Loan and Lease Losses, Total |  |  |  |  |  |  |  |  | $ 464,000 |

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