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Note 10 - Stockholders' Equity (Details Textual) - USD ($) | 12 Months Ended
--- | ---
Mar. 31, 2025 | Mar. 31, 2024 | Mar. 31, 2023
Dividends, Preferred Stock, Cash | $ 23,181 | $ 23,000 | $ 23,000
Common Stock, Capital Shares Reserved for Future Issuance | 33,695 | 33,695 |
Treasury Stock, Value, Acquired, Cost Method | $ 11,591,000 | $ 33,030,000 | $ 41,209,000
Treasury Stock, Shares, Acquired | 5,305,301 |  |
Treasury Stock, Value | $ 210,669,000 | 200,107,000 |
Defined Contribution Plan, Employer Discretionary Contribution Share Amount | 34,487 |  |
Defined Contribution Plan, Employer Discretionary Contribution Value of Shares | $ 1,000,000 |  |
Series A Preferred Stock [Member] |  |  |
Preferred Stock, Shares Authorized | 8,200,000 |  |
Preferred Stock, Par or Stated Value Per Share (in dollars per share) | $ 0.025 |  |
Preferred Stock, Dividend Rate, Percentage | 10.00% |  |
Preferred Stock, Stated Value Per Share (in dollars per share) | $ 0.25 |  |
Dividends, Preferred Stock, Cash | $ 10,181 | 10,181 |
Preferred Stock, Shares Non-designated | 6,792,109 |  |
Cumulative Convertible Preferred Stock, Series A, 10 Percent [Member] |  |  |
Preferred Stock, Shares Authorized | 1,000,000 |  |
Preferred Stock, Dividend Rate, Percentage | 10.00% |  |
Preferred Stock, Shares Outstanding (in shares) | 407,240 |  |
Convertible from Series A Preferred Stock to Class A Stock [Member] |  |  |
Share for Share Conversion Number (in shares) | 20 |  |
Series B Preferred Stock [Member] |  |  |
Preferred Stock, Shares Authorized | 400,000 |  |
Preferred Stock, Par or Stated Value Per Share (in dollars per share) | $ 0.025 |  |
Preferred Stock, Dividend Rate, Percentage | 10.00% |  |
Preferred Stock, Shares Outstanding (in shares) | 400,000 |  |
Preferred Stock, Stated Value Per Share (in dollars per share) | $ 0.25 |  |
Dividends, Preferred Stock, Cash | $ 10,000 | $ 10,000 |
Convertible from Series B Preferred Stock to Class A Stock [Member |  |  |
Share for Share Conversion Number (in shares) | 30 |  |
Convertible Preferred Stock [Member] |  |  |
Preferred Stock, Shares Outstanding (in shares) | 7,891 |  |
Convertible Preferred Stock, Shares Issued upon Conversion | 1 |  |
Preferred Stock, Dividends Per Share, Declared (in dollars per share) | $ 0 | $ 0 |
Preferred Stock, Liquidation Preference Per Share | $ 12 |  |
Conversion of Stock, Shares Converted (in shares) | 401 |  |
Cumulative Preferred Stock [Member] |  |  |
Preferred Stock, Shares Authorized | 200,000 |  |
Preferred Stock, Par or Stated Value Per Share (in dollars per share) | $ 0.25 |  |
Preferred Stock, Dividend Rate, Percentage | 6.00% |  |
Preferred Stock, Shares Outstanding (in shares) | 200,000 | 200,000 | 200,000
Dividends, Preferred Stock, Cash | $ 3,000 | $ 3,000 |
Preferred Stock, Dividends, Per Share, Cash Paid | $ 0.015 |  |
No Par Value Preferred Stock [Member] |  |  |
Preferred Stock, Shares Authorized | 30,000 |  |
Preferred Stock, Shares Outstanding (in shares) | 0 |  |
Common Class A [Member] |  |  |
Voting Rights, Percentage of Vote Per Share | 0.05% |  |
Stock Issued During Period, Shares, Employee Stock Ownership Plan | 3,870 |  |
Common Stock, Capital Shares Reserved for Future Issuance | 7,891 | 8,292 |
Treasury Stock, Value, Acquired, Cost Method | $ 11,600,000 |  |
Treasury Stock, Shares, Acquired | 194,370 |  |
Common Class B [Member] |  |  |
Stock Issued During Period, Profit Sharing Bonus Plan (in shares) | 108 |  |
Treasury Stock, Shares, Acquired | 0 |  |

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