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Note 5 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans - Restructurings By Class (Details) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2017 USD ($) | Dec. 31, 2016 USD ($) | Dec. 31, 2015 USD ($) | Dec. 31, 2014
Number of contracts |  | 10 | 4 | 6 |
Pre-modification outstanding principal balance |  | $ 1,387 | $ 3,042 | $ 3,628 |
Post-modification outstanding principal balance | [1] | $ 1,387 | $ 3,043 | $ 3,541 |
Consumer Real Estate Portfolio Segment [Member] | Closed End First Liens [Member] |  |  |  |  |
Number of contracts |  | 1 |  |  |
Pre-modification outstanding principal balance |  | $ 8 |  |  |
Post-modification outstanding principal balance | [1] | $ 8 |  |  |
Commercial Real Estate Portfolio Segment [Member] |  |  |  |  |
Number of contracts |  |  |  |  | 2
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Other [Member] |  |  |  |  |
Number of contracts |  | 1 | 2 |  |
Pre-modification outstanding principal balance |  | $ 132 | $ 3,008 |  |
Post-modification outstanding principal balance | [1] | $ 132 | $ 3,008 |  |
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate, Owner Occupied [Member] |  |  |  |  |
Number of contracts |  |  |  | 3 |
Pre-modification outstanding principal balance |  |  |  | $ 2,710 |
Post-modification outstanding principal balance | [1] |  |  | $ 2,623 |
Real Estate Construction Portfolio Segment[Member] | Construction, 1-4 Family Residential [Member] |  |  |  |  |
Number of contracts |  |  |  | 2 |
Pre-modification outstanding principal balance |  |  |  | $ 718 |
Post-modification outstanding principal balance | [1] |  |  | $ 718 |
Commercial Non Real Estate Segment [Member] |  |  |  |  |
Number of contracts |  |  | 1 |  |
Commercial Non Real Estate Segment [Member] | Commercial and Industrial [Member] |  |  |  |  |
Number of contracts |  | 4 | 1 | 1 |
Pre-modification outstanding principal balance |  | $ 1,221 | $ 29 | $ 200 |
Post-modification outstanding principal balance | [1] | $ 1,221 | $ 30 | $ 200 |
Consumer Non Real Estate Portfolio Segment [Member] | Automobile Loan [Member] |  |  |  |  |
Number of contracts |  | 4 | 1 |  |
Pre-modification outstanding principal balance |  | $ 26 | $ 5 |  |
Post-modification outstanding principal balance | [1] | $ 26 | $ 5 |  |
[1] | Post-modification outstanding recorded investment considers amounts immediately following the modification. Amounts do not reflect balances at the end of the period.

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- Definition Number of financing receivables that have been modified by troubled debt restructurings. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 33 -URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953676-111524 + Details
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