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Stockholders' Equity (narrative) (detail) - USD ($) | 12 Months Ended |
--- | --- | ---
Mar. 31, 2017 | Mar. 31, 2016 | Mar. 31, 2015 | Mar. 31, 2003
Cash dividends paid on preferred stock | $ 23,000 |  |  |
401 (k) match stock amount | $ 2,017,000 | $ 1,820,000 | $ 2,123,000 |
6% Cumulative Preferred Stock [Member] |  |  |  |
Preferred Stock, Dividend Rate, Percentage | 6.00% |  |  |
Preferred Stock, Par or Stated Value Per Share | $ 0.25 |  |  |
Preferred Stock, Shares Authorized | 200,000 |  |  |
Preferred Stock, Shares Outstanding | 200,000 | 200,000 | 200,000 |
Cash dividends paid on preferred stock | $ 3,000 | $ 3,000 | $ 3,000 |
10% Nonredeemable Convertible Preferred Stock [Member] |  |  |  |
Preferred Stock, Dividend Rate, Percentage | 10.00% |  |  |
Preferred Stock, Par or Stated Value Per Share | $ 0.025 |  |  |
Preferred Stock, Shares Authorized | 1,400,000 |  |  |
Preferred Stock, Shares Outstanding | 807,240 | 807,240 | 807,240 |
10% Series A Nonredeemable Convertible Preferred Stock [Member] |  |  |  |
Preferred Stock, Dividend Rate, Percentage | 10.00% |  |  |
Share For Share Conversion Number | 20 |  |  |
Preferred Stock, Shares Outstanding | 407,240 |  |  |
10% Series B Nonredeemable Convertible Preferred Stock [Member] |  |  |  |
Share For Share Conversion Number | 30 |  |  |
Preferred Stock, Shares Outstanding | 400,000 |  |  |
Participating Preferred Stock [Member] |  |  |  |
Preferred Stock Liquidation Preference | $ 12 |  |  |
Preferred Stock, Par or Stated Value Per Share | 0.025 |  |  |
Stated Value Per Share | $ 11.931 |  |  |
Preferred Stock, Shares Authorized | 90,826 |  |  |
Preferred Stock, Shares Outstanding | 89,251 | 90,826 | 90,826 |
Cash dividends paid on preferred stock | $ 20,000 | $ 20,000 | $ 20,000 |
2003 Series Participating Preferred Stock [Member] |  |  |  |
Preferred Stock Liquidation Preference | $ 15.5 |  |  |
Preferred Stock, Par or Stated Value Per Share | $ 0.025 |  |  |
Preferred Stock, Shares Authorized | 500 |  |  |
Preferred Stock, Shares Outstanding | 500 | 500 | 50,500 |
Price Per Share | $ 16.6 |  |  |
Preferred Stock Shares Issued |  |  |  | 967,742
No Par Value Preferred Stock [Member] |  |  |  |
Preferred Stock, Shares Authorized | 30,000 |  |  |
Class A Preferred Stock [Member] |  |  |  |
Preferred Stock, Par or Stated Value Per Share | $ 0.025 |  |  |
Preferred Stock, Shares Authorized | 8,200,000 |  |  |
Common Stock Capital Shares Reserved For Future Issuance | 89,751 | 91,326 |  |
Class A Preferred Non Designated Stock [Member] |  |  |  |
Preferred Stock, Shares Authorized | 6,710,249 |  |  |
Common Class A Member |  |  |  |
Common Stock Voting Right Per Share | $ 0.05 |  |  |
Treasury Stock, Value, Acquired, Cost Method | $ 2,400,000 |  |  |
Treasury Stock Shares Acquired | 73,400 |  |  |
Common Class B Member |  |  |  |
Treasury Stock, Value, Acquired, Cost Method | $ 400,000 |  |  |
Treasury Stock Shares Acquired | 9,042 |  |  |
Treasury Stock [Member] |  |  |  |
Treasury Stock, Value, Acquired, Cost Method | $ 66,500,000 |  |  |
Treasury Stock Shares Acquired | 2,300,146 |  |  |
401 (k) match shares | 63,846 |  |  |
401 (k) match stock amount | $ 2,000,000 |  |  |
Common Stock [Member] |  |  |  |
Common Stock Capital Shares Reserved For Future Issuance | 33,695 | 33,695 |  |

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