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Note 4 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans - Loans Past Due 90 Days or More and Impaired Loans (Details) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2016 | Mar. 31, 2015 | Dec. 31, 2015
Loans past due 90 days or more and still accruing |  | $ 328 |  | $ 272 | $ 156 |
Ratio of loans past due 90 days or more and still accruing to loans, net of unearned income and deferred fees |  | 0.05% |  | 0.04% | 0.03% |
Accruing restructured loans |  | $ 7,724 |  | $ 5,992 | $ 8,814 |
Impaired loans with no valuation allowance |  | 12,171 | [1],[2] | 11,265 | 12,973 | [1],[2]
Impaired loans with a valuation allowance |  | 1,818 | [1],[2] | 3,729 | 2,373 | [1],[2]
Total impaired loans |  | 13,989 | [1],[2] | 14,994 | 15,346 | [1],[2]
Valuation allowance |  | (80) | [1] | (236) | (45) | [1]
Impaired loans, net of allowance |  | 13,909 |  | 14,758 | 15,301 |
Average recorded investment in impaired loans(1) | [3],[4],[5] | 14,796 |  | 15,192 | 17,297 |
Interest income recognized on impaired loans, after designation as impaired | [3] | $ 125 |  | $ 174 | $ 769 |
[1] | Only classes with impaired loans are shown.
[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.
[4] | Recorded investment is net of charge-offs and interest paid while a loan is in nonaccrual status.
[5] | Recorded investment is net of charge-offs and interest paid while a loan is in nonaccrual status.

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- Definition Reflects the carrying amount of loans modified in a troubled debt restructuring that are accruing interest. + References No definition available. + Details
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- Definition Amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses, net of allowance. + References No definition available. + Details
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- Definition Represents ratio of loans past due 90 days or more and still accruing to loans, net of unearned income and deferred fees. + References No definition available. + Details
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- Definition Recorded investment in financing receivables that are 90 days or more past due and still accruing. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Recorded Investment -URI http://asc.fasb.org/extlink&oid=65880944 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 7 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=66008989&loc=d3e5111-111524 + Details
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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://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=66008989&loc=d3e5212-111524 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=66008989&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://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=66008989&loc=d3e5212-111524 + Details
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- Definition Amount of allowance for credit losses related to recorded investment. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Recorded Investment -URI http://asc.fasb.org/extlink&oid=65880944 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=66008989&loc=d3e5212-111524 + Details
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