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Note 6 - Investment Securities Available for Sale - Gross Unrealized Losses and Fair Value (Details) - USD ($) $ in Thousands | Jun. 30, 2017 | Dec. 31, 2016
--- | --- | ---
Total, Fair Value | $ 21,284 | $ 42,679
Total, Gross Unrealized Losses | (226) | (883)
Less than Twelve Months, Fair Value | 15,565 | 36,925
Less than Twelve Months, Gross Unrealized Losses | (96) | (699)
Twelve Months or Greater, Fair Value | 5,719 | 5,754
Twelve Months or Greater, Gross Unrealized Losses | (130) | (184)
US Government Agencies Debt Securities [Member] |  |
Total, Fair Value | 4,315 | 5,119
Total, Gross Unrealized Losses | (49) | (96)
Less than Twelve Months, Fair Value | 3,055 | 3,803
Less than Twelve Months, Gross Unrealized Losses | (17) | (47)
Twelve Months or Greater, Fair Value | 1,260 | 1,316
Twelve Months or Greater, Gross Unrealized Losses | (32) | (49)
US States and Political Subdivisions Debt Securities [Member] | Taxable [Member] |  |
Total, Fair Value | 505 | 502
Total, Gross Unrealized Losses | (2) | (4)
Less than Twelve Months, Fair Value | 505 | 502
Less than Twelve Months, Gross Unrealized Losses | (2) | (4)
Twelve Months or Greater, Fair Value |  |
Twelve Months or Greater, Gross Unrealized Losses |  |
US States and Political Subdivisions Debt Securities [Member] | Tax Exempt [Member] |  |
Total, Fair Value | 4,885 | 23,554
Total, Gross Unrealized Losses | (40) | (522)
Less than Twelve Months, Fair Value | 4,574 | 23,554
Less than Twelve Months, Gross Unrealized Losses | (40) | (522)
Twelve Months or Greater, Fair Value | 311 | 0
Twelve Months or Greater, Gross Unrealized Losses |  |
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] |  |
Total, Fair Value | 11,579 | 13,504
Total, Gross Unrealized Losses | (135) | (261)
Less than Twelve Months, Fair Value | 7,431 | 9,066
Less than Twelve Months, Gross Unrealized Losses | (37) | (126)
Twelve Months or Greater, Fair Value | 4,148 | 4,438
Twelve Months or Greater, Gross Unrealized Losses | $ (98) | $ (135)

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- Definition Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for twelve months or longer. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27290-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27337-111563 + Details
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- Definition Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale in a continuous loss position. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27337-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27290-111563 + Details
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- Definition Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for less than twelve months. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27290-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27337-111563 + Details
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