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Note 4 - Investment and Equity Securities (Details Textual) | 12 Months Ended
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Dec. 31, 2020 USD ($) | Dec. 31, 2019 USD ($)
Equity Securities, FV-NI |  | $ 609,000 | $ 710,000
Equity Securities, FV-NI, Unrealized Gain (Loss), Total | [1] | (101,000) | 94,000
Equity Securities, FV-NI, Realized Gain (Loss), Total |  | 0 | 0
Security Owned and Pledged as Collateral, Fair Value, Total |  | 71,100,000 | 55,600,000
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax, Total |  | $ 0 | 41,000
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions |  | 10 |
Available-for-sale Securities, Percentage of Portfolio |  | 81.40% |
Other-than-temporary Impairment Loss, Debt Securities, Available-for-sale, Total |  | $ 0 | $ 0
[1] | Not within scope of ASC 606

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- Definition Number of investments in debt securities measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position, without allowance for credit loss. Includes beneficial interest in securitized financial asset. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (b)(3) -URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27290-111563 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 50 -Paragraph 4 -Subparagraph (b)(3) -URI http://asc.fasb.org/extlink&oid=121582814&loc=SL82922888-210455 + Details
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- Definition Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 45 -Paragraph 1A -URI http://asc.fasb.org/extlink&oid=99377092&loc=SL75136599-209740 + Details
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- Definition Amount of realized gain (loss) from sale of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 321 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=120269885&loc=SL75117546-209714 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 220 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04(3)(d)) -URI http://asc.fasb.org/extlink&oid=120400993&loc=SL114874131-224263 + Details
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