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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, 2019 | Sep. 30, 2018 | Dec. 31, 2018
Loans past due 90 days or more and still accruing |  | $ 212 | [1] | $ 63 | $ 35 | [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% |  | 0.01% | 0.00% |
Accruing restructured loans |  | $ 1,880 |  | $ 7,843 | $ 2,552 |
Impaired loans: |  |  |  |  |  |
Impaired loans with no valuation allowance |  | 5,163 | [2] | 10,530 | 5,667 | [2]
Impaired loans with a valuation allowance |  | 1,070 | [2] | 1,404 | 1,153 | [2]
Total impaired loans |  | 6,233 | [2] | 11,934 | 6,820 | [2]
Valuation allowance |  | (120) |  | (156) | (139) |
Impaired loans, net of allowance |  | 6,113 |  | 11,778 | 6,681 |
Average recorded investment in impaired loans(1) | [3],[4] | 6,729 |  | 12,684 | 9,788 | [5]
Interest income recognized on impaired loans, after designation as impaired |  | 144 |  | 414 | 250 | [5]
Amount of income recognized on a cash basis |  | $ 0 |  | $ 0 |  |
[1] | Only classes with past-due or nonaccrual loans are shown.
[2] | Recorded investment is net of charge-offs and interest paid while a loan is in nonaccrual status.
[3] | Recorded investment is net of charge-offs and interest paid while a loan is in nonaccrual status.
[4] | Recorded investment is net of charge-offs and interest paid while a loan is in nonaccrual status.
[5] | Only classes with impaired loans are shown.

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