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Accounts Receivable (Details Textual) (USD $)
 9 Months Ended
Oct. 31, 2012
Jan. 31, 2012
Accounts Receivable (Textual) [Abstract]    
Allowance for doubtful accounts $ 5,600,000 $ 5,600,000
The amount of the net proceeds remaining from public auction of the partially completed project 5,500,000  
Account receivable from Solar Energy field project owner 2,100,000  
Grant for Advanced Payment for Project 7,800,000  
Reserve recorded against Project 0  
Maximum [Member]
    
Accounts Receivable (Textual) [Abstract]    
Length of retention holding period 2 years  
Minimum [Member]
    
Accounts Receivable (Textual) [Abstract]    
Length of retention holding period 9 months  
Construction Contracts Retainages [Member]
    
Accounts Receivable (Textual) [Abstract]    
Contract payment amounts retained by project owners $ 17,200,000 $ 9,800,000