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Note 5 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans - Loans Past Due 90 Days or More and Impaired Loans (Details) - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Loans past due 90 days or more and still accruing |  | $ 17 | [1] | $ 231 | [2] |  |
Ratio of loans past due 90 days or more and still accruing to loans, net of unearned income and deferred fees and costs |  | 0.00% |  | 0.03% |  |  |
Accruing restructured loans |  | $ 1,410 |  | $ 1,729 |  |  |
Impaired loans: |  |  |  |  |  |  |
Impaired loans with no valuation allowance | [3] | 3,858 |  | 4,174 |  |  |
Impaired loans with a valuation allowance | [3] | 1,045 |  | 1,115 |  |  |
Total impaired loans | [3] | 4,903 |  | 5,289 |  |  |
Valuation allowance |  | (75) |  | (110) |  |  |
Impaired loans, net of allowance |  | 4,828 |  | 5,179 |  |  |
Average recorded investment in impaired loans(1) |  | 5,093 | [3] | 5,359 | [3] | $ 9,788 | [4]
Income recognized on impaired loans, after designation as impaired |  | $ 54 |  | $ 171 |  | $ 250 |
[1] | Only classes with past due or nonaccrual loans are presented
[2] | Only classes with past-due or nonaccrual loans are shown.
[3] | Only classes with impaired loans are shown.
[4] | Recorded investment is net of charge-offs and interest paid while a loan is in nonaccrual status.

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