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Note 2 - Investments - Schedule of Debt Securities, Held-to-Maturity Credit Quality Indicators (Details) - USD ($) $ in Thousands | Sep. 30, 2025 | Dec. 31, 2024
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Debt Securities, Held-to-Maturity, Amortized Cost | $ 31,606 | $ 8,500
Corporate Debt Securities [Member] |  |
Debt Securities, Held-to-Maturity, Amortized Cost | 29,336 | 8,500
Municipal Bonds [Member] |  |
Debt Securities, Held-to-Maturity, Amortized Cost | 2,270 |
Standard & Poor's, BBB/BBB Minus Rating [Member] | Corporate Debt Securities [Member] |  |
Debt Securities, Held-to-Maturity, Amortized Cost | 29,336 | 8,500
Standard & Poor's, AA Rating [Member] | Municipal Bonds [Member] |  |
Debt Securities, Held-to-Maturity, Amortized Cost | $ 2,270 | $ 0

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- Definition Amount excluding accrued interest, before allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479344/326-20-45-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3B -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-3B Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-5 + Details
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