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Note 4 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans - Impaired Loans, Average Investment and Interest Income (Details) - USD ($) | 9 Months Ended | 12 Months Ended
--- | --- | ---
Sep. 30, 2016 | Sep. 30, 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] | $ 529,000 |  |  | $ 612,000
Interest income recognized on impaired loans, after designation as impaired | [1] | 0 |  |  | 23,000
Consumer Real Estate Portfolio Segment [Member] | Closed End First Liens [Member] |  |  |  |  |
Average recorded investment in impaired loans(1) | [1],[2] | 652,000 | $ 685,000 |  | 681,000
Interest income recognized on impaired loans, after designation as impaired | [1] | 28,000 | 33,000 |  | 43,000
Consumer Real Estate Portfolio Segment [Member] | Closed End Junior Liens [Member] |  |  |  |  |
Average recorded investment in impaired loans(1) | [1],[2] | 210,000 | 231,000 |  | 228,000
Interest income recognized on impaired loans, after designation as impaired | [1] | 10,000 | 11,000 |  | 15,000
Consumer Real Estate Portfolio Segment [Member] | Investor Owned Residential Real Estate [Member] |  |  |  |  |
Average recorded investment in impaired loans(1) | [1],[2] | 74,000 | 76,000 |  | 76,000
Interest income recognized on impaired loans, after designation as impaired | [1] | 3,000 | 4,000 |  | 5,000
Commercial Real Estate Portfolio Segment [Member] | Multifamily Real Estate [Member] |  |  |  |  |
Average recorded investment in impaired loans(1) | [1],[2] | 1,741,000 | 2,670,000 |  | 2,581,000
Interest income recognized on impaired loans, after designation as impaired | [1] | 7,000 | 0 |  | 84,000
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate, Owner Occupied [Member] |  |  |  |  |
Average recorded investment in impaired loans(1) | [1],[2] | 4,629,000 | 5,302,000 |  | 6,141,000
Interest income recognized on impaired loans, after designation as impaired | [1] | 175,000 | 86,000 |  | 251,000
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Other [Member] |  |  |  |  |
Average recorded investment in impaired loans(1) | [1],[2] | 4,372,000 | 5,924,000 |  | 5,888,000
Interest income recognized on impaired loans, after designation as impaired | [1] | 252,000 | 128,000 |  | 308,000
Commercial Non Real Estate Segment [Member] | Commercial and Industrial [Member] |  |  |  |  |
Average recorded investment in impaired loans(1) | [1],[2] | 697,000 | 1,014,000 |  | 1,090,000
Interest income recognized on impaired loans, after designation as impaired | [1] | 1,000 | 5,000 |  | 40,000
Consumer Non Real Estate Portfolio Segment [Member] | Automobile Loan [Member] |  |  |  |  |
Average recorded investment in impaired loans(1) | [2] | 4,000 |  |  |
Interest income recognized on impaired loans, after designation as impaired |  | 0 |  |  |
Average recorded investment in impaired loans(1) | [2],[3] | 12,908,000 | 15,902,000 | [1] | 17,297,000
Interest income recognized on impaired loans, after designation as impaired |  | $ 476,000 | $ 267,000 | [1] | $ 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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