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Note 5 - Loans and Related Allowance for Loan and Lease Losses - Additional Information on Impaired Loans (Details) - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2018 | Dec. 31, 2017
Average recorded investment | $ 13,558 | $ 12,836
Interest income recognized | 606 | 377
Commercial And Industrial [Member] |  |
Average recorded investment | 4,210 | 2,378
Interest income recognized | 172 | 123
Real Estate Construction Porfolio Segment [Member] |  |
Average recorded investment | 9 | 565
Interest income recognized |  | 20
Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member] |  |
Average recorded investment | 2,531 | 3,068
Interest income recognized | 57 | 75
Real Estate Mortgage Portfolio Segment [Member] | Commercial Loans [Member] |  |
Average recorded investment | 6,805 | 6,820
Interest income recognized | 377 | 159
Consumer Portfolio Segment [Member] |  |
Average recorded investment | 3 | 5
Interest income recognized |  |

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- Definition Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5212-111524 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5258-111524 + Details
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- Definition Amount of interest income recognized that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5212-111524 + Details
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