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Note 11 - Stockholders' Equity (Details Textual) - USD ($) | 12 Months Ended |  |
--- | --- | --- | ---
Mar. 31, 2024 | Mar. 31, 2023 | Mar. 31, 2022 | Dec. 31, 2003
Dividends, Preferred Stock, Cash | $ 23,181 |  |  |
Common Stock, Capital Shares Reserved for Future Issuance (in shares) | 33,695 | 33,695 |  |
Treasury Stock, Shares, Acquired (in shares) | 5,145,418 |  |  |
Treasury Stock, Value | $ 200,107,000 | $ 168,573,000 |  |
Defined Contribution Plan, Employer Discretionary Contribution Share Amount (in shares) | 55,055 |  |  |
Defined Contribution Plan, Employer Discretionary Contribution Value of Shares | $ 1,500,000 |  |  |
Convertible from Series A Preferred Stock to Class A Stock [Member] |  |  |  |
Share for Share Conversion Number (in shares) | 20 |  |  |
Convertible from Series B Preferred Stock to Class A Stock [Member |  |  |  |
Share for Share Conversion Number (in shares) | 30 |  |  |
Series A Preferred Stock [Member] |  |  |  |
Preferred Stock, Shares Authorized (in shares) | 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 (in shares) | 6,791,708 |  |  |
Cumulative Convertible Preferred Stock, Series A, 10 Percent [Member] |  |  |  |
Preferred Stock, Shares Authorized (in shares) | 1,000,000 |  |  |
Preferred Stock, Dividend Rate, Percentage | 10.00% |  |  |
Preferred Stock, Shares Outstanding (in shares) | 407,240 |  |  |
Series B Preferred Stock [Member] |  |  |  |
Preferred Stock, Shares Authorized (in shares) | 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 Preferred Stock [Member] |  |  |  |
Preferred Stock, Shares Outstanding (in shares) | 8,292 |  |  |
Convertible Preferred Stock, Shares Issued upon Conversion (in shares) | 1 |  |  |
Preferred Stock, Dividends Per Share, Declared (in dollars per share) | $ 0 | $ 0 |  |
Preferred Stock, Liquidation Preference Per Share (in dollars per share) | $ 12 |  |  |
Conversion of Stock, Shares Converted (in shares) | 0 |  |  |
Series 2003 Convertible Preferred Stock [Member] |  |  |  |
Preferred Stock, Shares Authorized (in shares) | 0 |  |  |
Preferred Stock, Shares Outstanding (in shares) | 0 | 0 | 500 |
Preferred Stock, Liquidation Preference Per Share (in dollars per share) | $ 15.5 |  |  |
Preferred Stock, Shares Issued (in shares) |  |  |  | 967,742
Sale of Stock, Price Per Share (in dollars per share) | $ 16.6 |  |  |
Cumulative Preferred Stock [Member] |  |  |  |
Preferred Stock, Shares Authorized (in shares) | 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 (in dollars per share) | $ 0.015 |  |  |
No Par Value Preferred Stock [Member] |  |  |  |
Preferred Stock, Shares Authorized (in shares) | 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 (in shares) | 4,864 |  |  |
Common Stock, Capital Shares Reserved for Future Issuance (in shares) | 8,292 | 8,292 |  |
Treasury Stock, Value, Acquired, Cost Method | $ 33,000,000 |  |  |
Treasury Stock, Shares, Acquired (in shares) | 634,231 |  |  |
Common Class B [Member] |  |  |  |
Stock Issued During Period, Profit Sharing Bonus Plan (in shares) | 1,571 |  |  |
Treasury Stock, Shares, Acquired (in shares) | 0 |  |  |

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