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Note 3 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans - Loans Past Due 90 Days or More and Impaired Loans (Details) - USD ($) $ in Thousands | 9 Months Ended | 12 Months Ended
--- | --- | ---
Sep. 30, 2020 | Sep. 30, 2019 | Dec. 31, 2019
Loans past due 90 days or more and still accruing |  | $ 236 | [1] | $ 212 | $ 231 | [1]
Ratio of loans past due 90 days or more and still accruing to loans, net of unearned income and deferred fees and costs |  | 0.03% |  | 0.03% | 0.03% |
Accruing restructured loans |  | $ 1,426 |  | $ 1,880 | $ 1,729 |
Impaired loans: |  |  |  |  |  |
Impaired loans with no valuation allowance |  | 3,939 | [2] | 5,163 | 4,174 | [2]
Impaired loans with a valuation allowance |  | 1,056 | [2] | 1,070 | 1,115 | [2]
Total impaired loans |  | 4,995 | [2] | 6,233 | 5,289 | [2]
Valuation allowance |  | (104) |  | (120) | (110) |
Impaired loans, net of allowance |  | 4,891 |  | 6,113 | 5,179 |
Average recorded investment in impaired loans(1) | [2] | 5,227 |  | 6,729 | 5,359 | [3]
Interest income recognized on impaired loans, after designation as impaired |  | $ 49 |  | $ 144 | $ 171 |
[1] | Only classes with past-due or nonaccrual loans are shown.
[2] | Only classes with impaired loans are shown.
[3] | Recorded investment is net of charge-offs and interest paid while a loan is in nonaccrual status.

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