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Note 8 - Investments, Including Investments Accounted for Using the Equity Method (Details Textual) - USD ($) |  |  |  |  | 1 Months Ended | 3 Months Ended | 12 Months Ended |
--- | --- | --- | --- | --- | --- | --- | --- | ---
Jan. 25, 2021 | Jan. 20, 2021 | May 31, 2018 | Dec. 31, 2017 | May 31, 2019 | Jan. 31, 2018 | Mar. 31, 2021 | Mar. 31, 2020 | Dec. 31, 2020 | Oct. 02, 2020
Gain (Loss) on Sale of Investments, Total |  |  |  |  |  |  | $ 2,840,170 | $ 26,268 |  |
Proceeds from Redemption of Preferred Units |  |  |  |  |  |  | 0 | 6,000,000 |  |
Equity Securities, FV-NI |  |  |  |  |  |  | 143,990,739 |  | $ 64,036,482 |
Payments to Acquire Equity Method Investments |  |  |  |  |  |  | (0) | $ 1,500,000 |  |
Dream Finders Holdings, LLC [Member] | Term Loan Receivable [Member] |  |  |  |  |  |  |  |  |  |
Notes Receivable, Related Parties |  |  |  |  |  |  |  |  |  | $ 20,000,000
Note Receivable, Interest Rate |  |  |  |  |  |  |  |  |  | 14.00%
Dream Finders Homes, Inc. [Member] |  |  |  |  |  |  |  |  |  |
Proceeds from Collection of Notes Receivable | $ 20,567,776 |  |  |  |  |  |  |  |  |
Common Class A [Member] | IPO [Member] | Dream Finders Homes, Inc. [Member] |  |  |  |  |  |  |  |  |  |
Stock Issued During Period, Shares, New Issues (in shares) |  | 9,600,000 |  |  |  |  |  |  |  |
Shares Issued, Price Per Share (in dollars per share) |  | $ 13.00 |  |  |  |  |  |  |  |
Unconsolidated Affiliates [Member] |  |  |  |  |  |  |  |  |  |
Equity Method Investments |  |  |  |  |  |  | $ 560,579 |  |  |
Unconsolidated Affiliates [Member] | Minimum [Member] |  |  |  |  |  |  |  |  |  |
Equity Method Investment, Ownership Percentage |  |  |  |  |  |  | 5.60% |  |  |
Unconsolidated Affiliates [Member] | Maximum [Member] |  |  |  |  |  |  |  |  |  |
Equity Method Investment, Ownership Percentage |  |  |  |  |  |  | 30.00% |  |  |
The 24th Street Fund I, LLC [Member] |  |  |  |  |  |  |  |  |  |
Equity Method Investment, Ownership Percentage |  |  |  |  |  |  | 49.90% |  |  |
Payments to Acquire Equity Method Investments |  |  |  |  |  |  | $ 6,000,000 |  |  |
Breezeway Homes Inc. [Member] |  |  |  |  |  |  |  |  |  |
Preferred Stock, Dividend Rate, Per-Dollar-Amount (in dollars per share) |  |  |  |  |  | $ 2,665 |  |  |  |
Preferred Stock [Member] | Breezeway Homes Inc. [Member] |  |  |  |  |  |  |  |  |  |
Debt Conversion, Converted Instrument, Shares Issued (in shares) |  |  |  |  |  | 31,227 |  |  |  |
US Treasury Notes Securities [Member] |  |  |  |  |  |  |  |  |  |
Gain (Loss) on Sale of Investments, Total |  |  |  |  |  |  | 23,904 |  |  |
Voting Common Stock of Privately Held Company CB&T Holding Corporation [Member] |  |  |  |  |  |  |  |  |  |
Payments to Acquire Long-term Investments |  |  | $ 19,058,485 |  |  |  |  |  |  |
Cost Method Investment, Ownership Percentage |  |  | 14.99% |  |  |  |  |  |  |
Equity Investments [Member] |  |  |  |  |  |  |  |  |  |
Other than Temporary Impairment Losses, Investments, Total |  |  |  |  |  |  | 0 |  |  |
Non-voting Common Units of Dream Finders Holdings, LLC [Member] |  |  |  |  |  |  |  |  |  |
Payments to Acquire Long-term Investments |  |  |  | $ 10,000,000 |  |  |  |  |  |
Cost Method Investment, Ownership Percentage |  |  |  | 5.60% |  |  |  |  |  |
Non-voting Preferred Units of DFH LLC [Member] |  |  |  |  |  |  |  |  |  |
Payments to Acquire Long-term Investments |  |  |  |  | $ 12,000,000 |  |  |  |  |
Mandatory Preferred Return, Percent |  |  |  |  | 14.00% |  |  |  |  |
Percent of Preferred Units Convertible to Non-voting Common Units |  |  |  |  | 25.00% |  |  |  |  |
Proceeds from Redemption of Preferred Units |  |  |  |  |  |  |  |  | $ 12,000,000 |
DFH Class A Common Stock [Member] |  |  |  |  |  |  |  |  |  |
Equity Securities, FV-NI, Shares, Acquired from Conversion (in shares) |  | 4,681,099 |  |  |  |  |  |  |  |
Equity Securities, FV-NI, Shares, Purchase (in shares) |  | 120,000 |  |  |  |  |  |  |  |
Equity Securities, FV-NI, Shares, Purchase, Price Per Share (in dollars per share) |  | $ 13.00 |  |  |  |  |  |  |  |
DFH Class A Common Stock [Member] | Minimum [Member] |  |  |  |  |  |  |  |  |  |
Equity Securities, FV-NI |  |  |  |  |  |  | $ 115,000,000 |  |  |

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