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Note 8 - Investments, Including Investments Accounted for Using the Equity Method - Marketable Equity Securities and Trading Securities (Details) - USD ($) | Dec. 31, 2020 | Dec. 31, 2019
--- | --- | ---
Marketable equity securities, Cost | $ 68,205,548 | $ 49,554,926
Marketable equity securities, Gross Unrealized Gain (Loss) | (4,169,066) | 6,353,001
Marketable equity securities | 64,036,482 | 55,907,927
U.S. Treasury trading securities, fair value | 37,767,945 | 75,409,199
US Treasury Notes Securities [Member] |  |
U.S. Treasury trading securities, cost | 37,766,133 | 75,488,863
U.S. Treasury trading securities, gross unrealized gain (loss) | 1,812 | (79,664)
U.S. Treasury trading securities, fair value | $ 37,767,945 | $ 75,409,199

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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). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 45 -Paragraph 1A -URI http://asc.fasb.org/extlink&oid=99377092&loc=SL75136599-209740 + Details
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- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in net income (trading). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121553693&loc=d3e26610-111562 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=121553693&loc=d3e26610-111562 + Details
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