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Note 8 - Investments, Including Investments Accounted for Using the Equity Method (Details Textual) - USD ($) |  |  |  |  |  | 1 Months Ended | 3 Months Ended | 9 Months Ended | 12 Months Ended |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Nov. 16, 2020 | Oct. 26, 2020 | Sep. 24, 2020 | May 31, 2018 | Dec. 31, 2017 | May 31, 2019 | Jan. 31, 2018 | May 01, 2021 | Dec. 31, 2020 | Sep. 30, 2020 | Dec. 31, 2020 | Dec. 31, 2019 | Dec. 01, 2020 | Dec. 31, 2018
Gain (Loss) on Sale of Investments, Total |  |  |  |  |  |  |  |  |  |  | $ 5,701,909 | $ 572,181 |  |
Proceeds from Redemption of Preferred Units |  |  |  |  |  |  |  |  |  |  | 12,000,000 | 0 |  |
Payments to Acquire Equity Method Investments |  |  |  |  |  |  |  |  |  |  | $ 5,715,625 | $ 264,834 |  |
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) |  |  |  |  |  |  |  |  | $ 9.95 |  | $ 9.95 | $ 9.95 |  | $ 9.95
Proceeds from Sale of Equity Method Investments |  |  |  |  |  |  |  |  |  |  | $ 309,375 | $ (0) |  |
Equity Method Investment, Gain (Loss) on Remeasurement |  |  |  |  |  |  |  |  |  |  | 5,074,587 | $ 0 |  |
Dream Finders Holdings, LLC [Member] | Term Loan Receivable [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Notes Receivable, Related Parties |  |  |  |  |  |  |  |  | $ 20,000,000 |  | $ 20,000,000 |  |  |
Note Receivable, Interest Rate |  |  |  |  |  |  |  |  | 14.00% |  | 14.00% |  |  |
Dream Finders Holdings, LLC [Member] | Term Loan Receivable [Member] | Forecast [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Note Receivable, Monthly Payments |  |  |  |  |  |  |  | $ 5,000,000 |  |  |  |  |  |
Common Class B [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Common Stock, Par or Stated Value Per Share (in dollars per share) |  |  |  |  |  |  |  |  | $ 1 |  | $ 1 | $ 1 |  |
BOC Yellowstone LLC [Member] | BOC Yellowstone II LLC [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of Investee's Shares Transferred to Related Party for No Consideration (in shares) | 206,250 |  |  |  |  |  |  |  |  |  |  |  |  |
Yellowstone Acquisition Company [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Common Stock, Par or Stated Value Per Share (in dollars per share) |  |  | $ 0.0001 |  |  |  |  |  |  |  |  |  |  |
Proceeds from Issuance Initial Public Offering |  | $ 125,000,000 |  |  |  |  |  |  |  |  |  |  |  |
Yellowstone Acquisition Company [Member] | Private Placement Warrants [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of Warrants Called by Each Unit (in shares) |  | 1.5 |  |  |  |  |  |  |  |  |  |  |  |
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares) |  | 1 |  |  |  |  |  |  | 1 |  | 1 |  |  |
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) |  | $ 11.50 |  |  |  |  |  |  | $ 11.50 |  | $ 11.50 |  | $ 11.50 |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) |  | 7,500,000 |  |  |  |  |  |  |  |  |  |  | 219,779 |
Price of Warrant (in dollars per share) |  | $ 1.00 |  |  |  |  |  |  | $ 1.00 |  | $ 1.00 |  | $ 1.00 |
Proceeds from Issuance of Warrants |  | $ 7,500,000 |  |  |  |  |  |  |  |  |  |  |  |
Yellowstone Acquisition Company [Member] | IPO [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of Units Issued (in shares) |  | 12,500,000 |  |  |  |  |  |  |  |  |  |  |  |
Number of Securities Called by Each Unit (in shares) |  | 1 |  |  |  |  |  |  |  |  |  |  |  |
Sale of Unit, Price Per Unit (in dollars per share) |  | $ 10.00 |  |  |  |  |  |  |  |  |  |  |  |
Yellowstone Acquisition Company [Member] | Common Class B [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Shares, Outstanding, Ending Balance (in shares) |  |  |  |  |  |  |  |  | 3,399,724 |  | 3,399,724 |  |  |
Yellowstone Acquisition Company [Member] | Common Class B [Member] | IPO [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Common Stock, Par or Stated Value Per Share (in dollars per share) |  | $ 0.0001 |  |  |  |  |  |  |  |  |  |  |  |
Unconsolidated Affiliates [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Equity Method Investments |  |  |  |  |  |  |  |  | $ 6,687,707 |  | $ 6,687,707 |  |  |
Unconsolidated Affiliates [Member] | Minimum [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Equity Method Investment, Ownership Percentage |  |  |  |  |  |  |  |  | 5.60% |  | 5.60% |  |  |
Unconsolidated Affiliates [Member] | Maximum [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Equity Method Investment, Ownership Percentage |  |  |  |  |  |  |  |  | 30.00% |  | 30.00% |  |  |
The 24th Street Fund I, LLC [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Payments to Acquire Equity Method Investments |  |  |  |  |  |  |  |  |  |  | $ 6,000,000 |  |  |
Yellowstone Acquisition Company [Member] | Unrealized Gain (Loss) on Securities [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Equity Method Investment, Gain (Loss) on Remeasurement |  |  |  |  |  |  |  |  |  |  | 5,074,587 |  |  |
Yellowstone Acquisition Company [Member] | BOC Yellowstone LLC [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Payments to Acquire Equity Method Investments |  |  | $ 25,000 |  |  |  |  |  |  |  |  |  |  |
Number of Affiliate's Shares Acquired (in shares) |  |  | 5,750,000 |  |  |  |  |  |  |  |  |  |  |
Number of Affiliate's Shares Surrendered for No Consideration (in shares) |  |  |  |  |  |  |  |  | 2,350,276 |  |  |  |  |
BOC Yellowstone II LLC [Member] | BOC Yellowstone LLC [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proceeds from Sale of Equity Method Investments | $ 309,375 |  |  |  |  |  |  |  |  |  |  |  |  |
Breezeway Homes Inc. [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Preferred Stock, Dividend Rate, Per-Dollar-Amount (in dollars per share) |  |  |  |  |  |  | $ 2,665 |  |  |  |  |  |  |
Lead Investor in Yellowstone’s IPO [Member] | BOC Yellowstone LLC [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of Investee's Shares Agreed to Transfer Upon Business Combination (in shares) | 206,250 |  |  |  |  |  |  |  |  |  |  |  |  |
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 |  |  |  |  |  |  |  |  |  |  | 13,159 |  |  |
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% |  |  |  |  |  |  |  |  |  |
Non-voting Common Units of 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 |  |  |  |
Equity Investments [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other than Temporary Impairment Losses, Investments, Total |  |  |  |  |  |  |  |  |  |  | $ 0 | $ 0 |  |

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