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Note 5 - Securities - Securities Available-for-sale (Details) - USD ($) | Sep. 30, 2016 | Dec. 31, 2015
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US Government Agencies Debt Securities [Member] |  |
Securities available-for-sale, Amortized Costs | $ 268,925,000 | $ 216,897,000
Securities available-for-sale, Gross Unrealized Gains | 2,038,000 | 519,000
Securities available-for-sale, Gross Unrealized Losses | 253,000 | 4,952,000
Securities available-for-sale, Fair Values | 270,710,000 | 212,464,000
US States and Political Subdivisions Debt Securities [Member] |  |
Securities available-for-sale, Amortized Costs | 12,572,000 | 15,934,000
Securities available-for-sale, Gross Unrealized Gains | 352,000 | 541,000
Securities available-for-sale, Gross Unrealized Losses | 0 | 0
Securities available-for-sale, Fair Values | 12,924,000 | 16,475,000
Collateralized Mortgage Backed Securities [Member] |  |
Securities available-for-sale, Amortized Costs | 932,000 | 1,199,000
Securities available-for-sale, Gross Unrealized Gains | 103,000 | 120,000
Securities available-for-sale, Gross Unrealized Losses | 0 | 0
Securities available-for-sale, Fair Values | 1,035,000 | 1,319,000
Corporate Debt Securities [Member] |  |
Securities available-for-sale, Amortized Costs | 6,016,000 | 6,015,000
Securities available-for-sale, Gross Unrealized Gains | 440,000 | 22,000
Securities available-for-sale, Gross Unrealized Losses |  | 291,000
Securities available-for-sale, Fair Values | 6,456,000 | 5,746,000
Other Securities [Member] |  |
Securities available-for-sale, Amortized Costs | 189,000 | 189,000
Securities available-for-sale, Gross Unrealized Gains | 0 | 0
Securities available-for-sale, Gross Unrealized Losses | 37,000 | 62,000
Securities available-for-sale, Fair Values | 152,000 | 127,000
Securities available-for-sale, Amortized Costs | 288,634,000 | 240,234,000
Securities available-for-sale, Gross Unrealized Gains | 2,933,000 | 1,202,000
Securities available-for-sale, Gross Unrealized Losses | 290,000 | 5,305,000
Securities available-for-sale, Fair Values | $ 291,277,000 | $ 236,131,000

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- Definition Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 25 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=65884222&loc=d3e22054-111558 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=66010992&loc=d3e26610-111562 + Details
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- Definition Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27161-111563 + Details
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- Definition Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27161-111563 + Details
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- Definition This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.2) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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