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Note 4 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans (Details Textual) | 3 Months Ended | 9 Months Ended | 12 Months Ended
--- | --- | --- | ---
Sep. 30, 2016 USD ($) | Jun. 30, 2016 | Sep. 30, 2015 USD ($) | Sep. 30, 2016 USD ($) | Sep. 30, 2015 USD ($) | Dec. 31, 2015 USD ($)
Nonperforming Financial Instruments [Member] |  |  |  |  |  |
Interest and Fee Income, Loans and Leases |  |  |  | $ 0 | $ 0 | $ 0
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Other [Member] | Forgive Principal, Reduce Interest Rate, Capitalize Interest, and Re-amortize Payments [Member] |  |  |  |  |  |
Allowance for Credit Losses, Change in Method of Calculating Impairment | $ 0 |  |  | $ 0 |  |
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Other [Member] |  |  |  |  |  |
Financing Receivable, Modifications, Number of Contracts |  | 2 |  | 2 |  |
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate, Owner Occupied [Member] | Forgive Principal, Reduce Interest Rate, Capitalize Interest, and Re-amortize Payments [Member] |  |  |  |  |  |
Financing Receivable Modifications Principal Forgiven |  |  |  |  | $ 100,000 |
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate, Owner Occupied [Member] |  |  |  |  |  |
Financing Receivable, Modifications, Number of Contracts |  |  |  |  | 1 |
Commercial Non Real Estate Segment [Member] | Commercial and Industrial [Member] |  |  |  |  |  |
Financing Receivable, Modifications, Number of Contracts | 1 |  |  | 1 |  |
Consumer Non Real Estate Portfolio Segment [Member] | Automobile Loan [Member] |  |  |  |  |  |
Financing Receivable, Modifications, Number of Contracts | 1 |  |  | 1 |  |
Special Mention [Member] |  |  |  |  |  |
Increase in Percentage of Allocation Loans Rated Special Mention |  |  |  | 50.00% |  |
Classified Excluding Impaired [Member] |  |  |  |  |  |
Increase in Percentage of Allocation Loans Rated Classified |  |  |  | 100.00% |  |
Interest and Fee Income, Loans and Leases | $ 7,409,000 |  | $ 7,676,000 | $ 22,032,000 | $ 22,886,000 |
Financing Receivable, Reclassification to Held-for-sale |  |  |  | 0 |  |
Transfer of Loans Held-for-sale to Portfolio Loans |  |  |  | $ 0 |  |
Financing Receivable, Modifications, Number of Contracts | 2 |  | 0 | 4 | 1 |
Financing Receivable, Modifications, Subsequent Default, Number of Contracts |  |  |  | 0 | 0 |
Threshold for Designation to Impaired Status |  |  |  | $ 250,000 |  |
Threshold Period for Considering Loans as Special Mention or Classified |  |  |  | 75 days |  |
Financing Receivable, Modifications, Recorded Investment | $ 8,563,000 |  | $ 11,861,000 | $ 8,563,000 | $ 11,861,000 | $ 13,453,000

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