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Note 8 - Investments, Including Investments Accounted for Using the Equity Method - Schedule of Investments (Details) - USD ($) | Dec. 31, 2019 | Dec. 31, 2018
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Short-term Investments | $ 6,547,171 | $ 6,251,064
Long-term investments | 42,638,240 | 32,381,686
Certificates of Deposit [Member] |  |
Short-term Investments | 987,599 | 1,378,666
Long-term investments | 380,753 | 317,178
US Treasury Securities [Member] |  |
Short-term Investments | 4,649,572 | 4,872,398
Long-term investments | 1,094,983 | 2,902,004
Corporate Bond Securities [Member] |  |
Short-term Investments | 910,000 |
Preferred Stock [Member] |  |
Long-term investments | 104,019 | 104,019
Non-voting Preferred Units of DFH LLC [Member] |  |
Long-term investments | 12,000,000 |
Non-voting Common Units of LLC [Member] |  |
Long-term investments | 10,000,000 | 10,000,000
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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