XML 46 R36.htm IDEA: XBRL DOCUMENT v2.4.0.6
Accounting Policies (Detail) (USD $)
 3 Months Ended 12 Months Ended
Apr. 30, 2013
Apr. 30, 2012
Jan. 31, 2013
Interest Costs Capitalized $ 0 $ 0  
Interest Paid 981,000 1,582,000  
Derivative Settlement on Interest Rate Swap 440,000 483,000  
Income Taxes Paid 0 0  
Proceeds from Income Tax Refunds 0 0  
Unrecognized Tax Benefit 1,768,000    
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued 405,000    
Unrecognized Tax Benefits that Would Impact Effective Tax Rate 82,000    
Inventory Write-down 1,000   466,000
Property, Plant and Equipment, Depreciation Methods Depreciation is computed using the straight-line method    
Impairment of Real Estate $ 0 $ 0  
Estimated Cash Flow Percentage 25.00%    
Estimated Future Cash Flows Terms six    
Plant Operation Suspension 6 months    
Number of Majority Owned Subsidiaries 2    
Maximum Percentage of Equity Ownership Interest Which May be Considered for Equity Method of Accounting 20.00%    
Building and Building Improvements [Member] | Minimum [Member]
      
Property, Plant and Equipment, Estimated Useful Lives 15    
Building and Building Improvements [Member] | Maximum [Member]
      
Property, Plant and Equipment, Estimated Useful Lives 40    
Fixtures And Equipment [Member] | Minimum [Member]
      
Property, Plant and Equipment, Estimated Useful Lives 3    
Fixtures And Equipment [Member] | Maximum [Member]
      
Property, Plant and Equipment, Estimated Useful Lives 20    
Minimum [Member]
      
Extended Period of Warranty 12 months    
Maximum [Member]
      
Extended Period of Warranty 60 months