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Note 5 - Loans and Related Allowance for Loan and Lease Losses - Troubled Debt Restructurings (Details) $ in Thousands | 12 Months Ended
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Dec. 31, 2018 USD ($) | Dec. 31, 2017 USD ($)
Number of contracts |  |
Pre-modification outstanding recorded investment | $ 424 | $ 383
Post-modification outstanding recorded investment | $ 424 | $ 383
Commercial And Industrial [Member] |  |
Number of contracts | 1 | 4
Pre-modification outstanding recorded investment | $ 44 | $ 127
Post-modification outstanding recorded investment | $ 44 | $ 127
Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member] |  |
Number of contracts | 5 | 5
Pre-modification outstanding recorded investment | $ 286 | $ 256
Post-modification outstanding recorded investment | $ 286 | $ 256
Commercial Real Estate Portfolio Segment [Member] |  |
Number of contracts | 1 |
Pre-modification outstanding recorded investment | $ 94 |
Post-modification outstanding recorded investment | $ 94 |
Extended Maturity [Member] |  |
Number of contracts |  |
Extended Maturity [Member] | Commercial And Industrial [Member] |  |
Number of contracts | 1 | 4
Extended Maturity [Member] | Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member] |  |
Number of contracts | 3 | 5
Extended Maturity [Member] | Commercial Real Estate Portfolio Segment [Member] |  |
Number of contracts | 1 |
Other Restructurings [Member] |  |
Number of contracts |  |
Other Restructurings [Member] | Commercial And Industrial [Member] |  |
Number of contracts |  |
Other Restructurings [Member] | Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member] |  |
Number of contracts | 2 |
Other Restructurings [Member] | Commercial Real Estate Portfolio Segment [Member] |  |
Number of contracts |  |

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- Definition Post-modification amount of investment in financing receivables modified by troubled debt restructurings. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -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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