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Note 4 - Investment and Equity Securities (Details Textual) | 12 Months Ended
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Dec. 31, 2022 USD ($) | Dec. 31, 2021 USD ($)
Equity Securities, FV-NI, Current |  | $ 915,000 | $ 818,000
Equity Securities, FV-NI, Unrealized Gain (Loss), Total | [1] | (173,000) | 209,000
Equity Securities, FV-NI, Realized Gain (Loss), Total |  | 0 | 0
Proceeds from Sale and Maturity of Marketable Securities |  | 57,887,000 | 0
Realized Investment Gains (Losses), Total |  | $ 0 |
Proceeds from Sale of Investment Securities |  |  | 0
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Number of Positions |  | 141 |
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions |  | 60 |
Available-for-sale Securities, Percentage of Portfolio |  | 81.70% |
Other-than-temporary Impairment Loss, Debt Securities, Available-for-sale, Total |  | $ 0 | 0
Asset Pledged as Collateral [Member] | Deposits [Member] |  |  |
Financial Instruments, Owned, at Fair Value, Total |  | $ 89,900,000 | $ 77,100,000
[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 continuous unrealized loss position for 12 months or longer, without an allowance for credit loss. Includes beneficial interest in securitized financial asset. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 50 -Paragraph 4 -Subparagraph (b)(3) -URI https://asc.fasb.org/extlink&oid=124269663&loc=SL82922888-210455 + Details
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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 continuous unrealized loss position for less than 12 months, without an allowance for credit loss. Includes beneficial interest in securitized financial asset. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 50 -Paragraph 4 -Subparagraph (b)(3) -URI https://asc.fasb.org/extlink&oid=124269663&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), classified as current. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(2)) -URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section 45 -Paragraph 1 -Subparagraph (f) -URI https://asc.fasb.org/extlink&oid=124098289&loc=d3e6676-107765 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 45 -Paragraph 1A -URI https://asc.fasb.org/extlink&oid=123594786&loc=SL75136599-209740 + Details
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