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Note 4 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans - Impaired Loans, Average Investment and Interest Income (Details) - USD ($) | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2016 | Mar. 31, 2015 | Dec. 31, 2015
Real Estate Construction Portfolio Segment[Member] | Construction, 1-4 Family Residential [Member] |  |  |  |  |  |  |
Average recorded investment in impaired loans(1) | [1],[2] | $ 682,000 |  |  |  | $ 612,000 |
Interest income recognized on impaired loans, after designation as impaired |  | 0 |  |  |  | 23,000 |
Consumer Real Estate Portfolio Segment [Member] | Closed End First Liens [Member] |  |  |  |  |  |  |
Average recorded investment in impaired loans(1) | [1],[2] | 667,000 |  | $ 501,000 |  | 681,000 |
Interest income recognized on impaired loans, after designation as impaired |  | 10,000 | [2] | 7,000 |  | 43,000 | [2]
Consumer Real Estate Portfolio Segment [Member] | Closed End Junior Liens [Member] |  |  |  |  |  |  |
Average recorded investment in impaired loans(1) | [1],[2] | 216,000 |  | 236,000 |  | 228,000 |
Interest income recognized on impaired loans, after designation as impaired | [2] | 4,000 |  | 4,000 |  | 15,000 |
Consumer Real Estate Portfolio Segment [Member] | Investor Owned Residential Real Estate [Member] |  |  |  |  |  |  |
Average recorded investment in impaired loans(1) | [1],[2] | 75,000 |  | 76,000 |  | 76,000 |
Interest income recognized on impaired loans, after designation as impaired | [2] | 1,000 |  | 1,000 |  | 5,000 |
Commercial Real Estate Portfolio Segment [Member] | Multifamily Real Estate [Member] |  |  |  |  |  |  |
Average recorded investment in impaired loans(1) | [1],[2] | 1,595,000 |  | 2,708,000 |  | 2,581,000 |
Interest income recognized on impaired loans, after designation as impaired |  | 0 | [1] | 25,000 | [2] | 84,000 | [1]
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate, Owner Occupied [Member] |  |  |  |  |  |  |
Average recorded investment in impaired loans(1) | [1],[2] | 4,949,000 |  | 4,974,000 |  | 6,141,000 |
Interest income recognized on impaired loans, after designation as impaired | [1] | 68,000 |  | 58,000 |  | 251,000 |
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Other [Member] |  |  |  |  |  |  |
Average recorded investment in impaired loans(1) | [1],[2] | 5,793,000 |  | 6,023,000 |  | 5,888,000 |
Interest income recognized on impaired loans, after designation as impaired | [1] | 42,000 |  | 80,000 |  | 308,000 |
Commercial Non Real Estate Segment [Member] | Commercial and Industrial [Member] |  |  |  |  |  |  |
Average recorded investment in impaired loans(1) | [1],[2] | 819,000 |  | 674,000 |  | 1,090,000 |
Interest income recognized on impaired loans, after designation as impaired | [1] | 0 |  | (1,000) |  | 40,000 |
Average recorded investment in impaired loans(1) | [1],[2],[3] | 14,796,000 |  | 15,192,000 |  | 17,297,000 |
Interest income recognized on impaired loans, after designation as impaired | [1] | $ 125,000 |  | $ 174,000 |  | $ 769,000 |
[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] | Recorded investment is net of charge-offs and interest paid while a loan is in nonaccrual status.

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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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