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Note 3 - Investment Securities Available for Sale - Amortized Cost and Fair Values of Securities Available for Sale (Details) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016
--- | --- | ---
Amortized cost | $ 93,631 | $ 112,557
Gross unrealized gains | 2,048 | 2,702
Gross unrealized losses | (396) | (883)
Investment securities available for sale, at fair value | 95,283 | 114,376
US Government Agencies Debt Securities [Member] |  |
Amortized cost | 8,664 | 10,158
Gross unrealized gains | 126 | 174
Gross unrealized losses | (71) | (96)
Investment securities available for sale, at fair value | 8,719 | 10,236
US States and Political Subdivisions Debt Securities [Member] |  |
Investment securities available for sale, at fair value | 67,429 | 81,223
US States and Political Subdivisions Debt Securities [Member] | Taxable [Member] |  |
Amortized cost | 504 | 1,615
Gross unrealized gains | 8 | 129
Gross unrealized losses |  | (4)
Investment securities available for sale, at fair value | 512 | 1,740
US States and Political Subdivisions Debt Securities [Member] | Tax Exempt [Member] |  |
Amortized cost | 65,408 | 78,327
Gross unrealized gains | 1,547 | 1,678
Gross unrealized losses | (38) | (522)
Investment securities available for sale, at fair value | 66,917 | 79,483
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] |  |
Amortized cost | 18,640 | 20,128
Gross unrealized gains | 157 | 202
Gross unrealized losses | (287) | (261)
Investment securities available for sale, at fair value | 18,510 | 20,069
Debt Securities [Member] |  |
Amortized cost | 93,216 | 111,807
Gross unrealized gains | 1,838 | 2,313
Gross unrealized losses | (396) | (883)
Investment securities available for sale, at fair value | 94,658 | 113,237
Mortgage-backed Securities, Issued by Private Enterprises [Member] |  |
Amortized cost |  | 1,579
Gross unrealized gains |  | 130
Gross unrealized losses |  |
Investment securities available for sale, at fair value |  | 1,709
Equity Securities In Financial Institutions [Member] |  |
Amortized cost | 415 | 750
Gross unrealized gains | 210 | 389
Gross unrealized losses |  |
Investment securities available for sale, at fair value | $ 625 | $ 1,139

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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=75030427&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=82897076&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=82896770&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=82897076&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=82897076&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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