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Note 2 - Securities - Available-for-sale Securities (Details) - USD ($) | Jun. 30, 2018 | Dec. 31, 2017
--- | --- | ---
Securities available for sale, amortized cost | $ 344,921,000 | $ 341,948,000
Securities available for sale, gross unrealized gains | 639,000 | 1,355,000
Securities available for sale, gross unrealized losses | (14,418,000) | (7,559,000)
Securities available for sale, fair value | 331,142,000 | 335,744,000
US Government Agencies Debt Securities [Member] |  |
Securities available for sale, amortized cost | 193,956,000 | 175,953,000
Securities available for sale, gross unrealized gains | 29,000 | 99,000
Securities available for sale, gross unrealized losses | (11,805,000) | (6,352,000)
Securities available for sale, fair value | 182,180,000 | 169,700,000
Collateralized Mortgage Backed Securities [Member] |  |
Securities available for sale, amortized cost | 45,397,000 | 38,967,000
Securities available for sale, gross unrealized gains | 224,000 | 335,000
Securities available for sale, gross unrealized losses | (1,064,000) | (510,000)
Securities available for sale, fair value | 44,557,000 | 38,792,000
Municipal General Obligation Bonds [Member] |  |
Securities available for sale, amortized cost | 101,252,000 | 121,040,000
Securities available for sale, gross unrealized gains | 381,000 | 891,000
Securities available for sale, gross unrealized losses | (1,481,000) | (638,000)
Securities available for sale, fair value | 100,152,000 | 121,293,000
Municipal Revenue Bonds [Member] |  |
Securities available for sale, amortized cost | 3,816,000 | 3,978,000
Securities available for sale, gross unrealized gains | 5,000 | 30,000
Securities available for sale, gross unrealized losses | (68,000) | (30,000)
Securities available for sale, fair value | 3,753,000 | 3,978,000
Other Debt and Equity Securities [Member] |  |
Securities available for sale, amortized cost | 500,000 | 2,010,000
Securities available for sale, gross unrealized gains | 0 | 0
Securities available for sale, gross unrealized losses | 0 | (29,000)
Securities available for sale, fair value | $ 500,000 | $ 1,981,000

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- Definition Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -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 investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -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 Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563 + Details
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