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Note 8 - Investments, Including Investments Accounted for Using the Equity Method - Schedule of Investments (Details) - USD ($) | Dec. 31, 2022 | Dec. 31, 2021
--- | --- | ---
Short-term Investments | $ 6,288,828 | $ 4,728,995
Long-term investments | 26,136,636 | 19,316,769
Certificates of Deposit [Member] |  |
Short-term Investments | 0 | 310,276
US Treasury Securities [Member] |  |
Long-term investments | 6,729,457 | 154,265
U.S. Treasury Notes and Corporate Bonds [Member] |  |
Short-term Investments | 4,757,224 | 4,418,719
Preferred Stock [Member] |  |
Long-term investments | 348,694 | 104,019
Common Stock Warrants of Sky Harbour Group Corporation [Member] |  |
Short-term Investments | 1,531,604 | 0
Voting Common Stock of Privately Held Company CB&T Holding Corporation [Member] |  |
Long-term investments | $ 19,058,485 | $ 19,058,485

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