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Accounts Receivable - Additional Information (Detail) (USD $)
 3 Months Ended 9 Months Ended
Oct. 31, 2014
Oct. 31, 2014
Jan. 31, 2014
Jan. 31, 2010
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Length of retention period of amount given to project owners   2 years    
Allowance for doubtful accounts $ 5,500,000 $ 5,500,000 $ 5,500,000  
Accounts receivable from the owner of a partially completed construction project       5,500,000
Provision for accounts receivable loss 0 0    
Construction Contracts Retainage [Member]
        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Contract payment amounts retained by project owners $ 21,000,000 $ 21,000,000 $ 22,700,000