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Note 3 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans - Impaired Loans, Average Investment and Interest Income (Details) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2018 | Mar. 31, 2017 | Dec. 31, 2017
Average recorded investment in impaired loans(1) | [1],[2] | $ 11,754 |  | $ 9,123 | $ 13,344 | [3]
Interest income recognized on impaired loans, after designation as impaired |  | 120 |  | 67 | 528 | [3]
Real Estate Construction Portfolio Segment[Member] | Construction, 1-4 Family Residential [Member] |  |  |  |  |  |
Average recorded investment in impaired loans(1) | [2],[3] | 839 |  | 267 | 3,298 |
Interest income recognized on impaired loans, after designation as impaired | [3] | 38 |  | 3 | 177 |
Consumer Real Estate Portfolio Segment [Member] | Closed End First Liens [Member] |  |  |  |  |  |
Average recorded investment in impaired loans(1) | [2],[3] | 3,387 |  | 606 | 781 |
Interest income recognized on impaired loans, after designation as impaired | [3] | 10 |  | 9 | 57 |
Consumer Real Estate Portfolio Segment [Member] | Closed End Junior Liens [Member] |  |  |  |  |  |
Average recorded investment in impaired loans(1) | [2],[3] | 253 |  | 193 | 185 |
Interest income recognized on impaired loans, after designation as impaired | [3] | 3 |  | 3 | 11 |
Consumer Real Estate Portfolio Segment [Member] | Investor Owned Residential Real Estate [Member] |  |  |  |  |  |
Average recorded investment in impaired loans(1) | [2],[3] | 323 |  | 73 | 329 |
Interest income recognized on impaired loans, after designation as impaired | [3] | 4 |  | 1 | 1 |
Commercial Real Estate Portfolio Segment [Member] | Multifamily Real Estate [Member] |  |  |  |  |  |
Average recorded investment in impaired loans(1) | [2],[3] | 372 |  | 1,091 | 748 |
Interest income recognized on impaired loans, after designation as impaired | [3] | 4 |  |  | 16 |
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate, Owner Occupied [Member] |  |  |  |  |  |
Average recorded investment in impaired loans(1) | [2],[3] | 2,648 |  | 3,945 | 4,047 |
Interest income recognized on impaired loans, after designation as impaired | [3] | 50 |  | 32 | 200 |
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Other [Member] |  |  |  |  |  |
Average recorded investment in impaired loans(1) | [2],[3] | 2,384 |  | 2,708 | 2,638 |
Interest income recognized on impaired loans, after designation as impaired | [3] |  |  | 17 |  |
Commercial Non Real Estate Segment [Member] | Commercial and Industrial [Member] |  |  |  |  |  |
Average recorded investment in impaired loans(1) | [2],[3] | 939 |  | 237 | 1,282 |
Interest income recognized on impaired loans, after designation as impaired | [3] | 11 |  | 2 | 64 |
Consumer Non Real Estate Portfolio Segment [Member] | Automobile Loan [Member] |  |  |  |  |  |
Average recorded investment in impaired loans(1) | [2] | 609 | [3] | 3 | 36 |
Interest income recognized on impaired loans, after designation as impaired |  |  | [3] | $ 0 | $ 2 | [3]
[1] | Recorded investment is net of charge-offs and interest paid while a loan is in nonaccrual status.
[2] | Recorded investment is net of charge-offs and interest paid while a loan is in nonaccrual status.
[3] | Only classes with impaired loans are shown.

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