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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, 2021 | Sep. 30, 2020 | Dec. 31, 2020
Loans past due 90 days or more and still accruing |  | $ 62 |  | $ 236 | $ 17 |
Ratio of loans past due 90 days or more and still accruing to loans, net of unearned income and deferred fees and costs |  | 0.01% |  | 0.03% | 0.00% |
Accruing restructured loans |  | $ 3,009 |  | $ 1,426 | $ 1,410 |
Impaired loans: |  |  |  |  |  |
Impaired loans with no valuation allowance |  | 6,084 | [1] | 3,939 | 3,858 | [1]
Impaired loans with a valuation allowance |  | 0 | [1] | 1,056 | 1,045 | [1]
Total impaired loans |  | 6,084 | [1] | 4,995 | 4,903 | [1]
Valuation allowance |  | 0 |  | (104) | (75) |
Impaired loans, net of allowance |  | 6,084 |  | 4,891 | 4,828 |
Average recorded investment in impaired loans(1) | [1] | 6,108 |  | 5,227 | 5,093 |
Interest income recognized on impaired loans, after designation as impaired |  | $ 175 |  | $ 49 | $ 54 |
[1] | Recorded investment is net of charge-offs and interest paid while a loan is in nonaccrual status.

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