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Note 8 - Investments, Including Investments Accounted for Using the Equity Method - Schedule of Investments (Details) - USD ($) | Sep. 30, 2021 | Dec. 31, 2020
--- | --- | ---
Short-term Investments | $ 4,978,644 | $ 7,050,675
Long-term investments | 19,316,769 | 19,448,519
Certificates of Deposit [Member] |  |
Short-term Investments | 310,044 | 1,035,827
US Treasury Securities [Member] |  |
Long-term investments | 154,265 | 286,015
Corporate Bond Securities [Member] |  |
Short-term Investments | 0 | 1,020,000
Preferred Stock [Member] |  |
Long-term investments | 104,019 | 104,019
U.S. Treasury Notes and Corporate Bonds [Member] |  |
Short-term Investments | 4,668,600 | 4,994,848
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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