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Stockholders' Equity - Additional Information (Detail) (USD $)
 12 Months Ended
Jan. 31, 2014
Jan. 31, 2013
Jan. 31, 2012
Sep. 30, 2011
Stockholders Equity [Line Items]        
Common stock, shares, repurchase program       2,000,000
Repurchases of common stock     125,000  
Repurchases of stock, value     $ 2,929,000  
Share repurchase description The Company's credit agreement prohibited the repurchase of shares until February 2014, after which repurchases may be made subject to compliance with certain covenants.      
Shares available for grant 682,330      
Expected dividend yield 0.00% 0.00% 0.00%  
Weighted average remaining term for stock options outstanding 5 years 8 months 12 days      
Aggregate intrinsic value for stock options outstanding 12,800,000      
Aggregate intrinsic value for stock options exercisable 8,200,000      
Proceeds from exercise of stock options 1,900,000 1,400,000    
Intrinsic value of stock options exercised 4,000,000 2,600,000    
Unrecognized stock compensation related to unvested option awards 1,000,000      
Expected date through which unrecognized stock compensation is recognized Jan. 31, 2018      
Weighted average grant date fair value   $ 12.06 $ 12.97  
Maximum
        
Stockholders Equity [Line Items]        
Term of option awards 10 years      
Restricted Stock Units (RSUs)
        
Stockholders Equity [Line Items]        
Recognized compensation expense 9,200,000 7,000,000    
Unrecognized stock compensation related to restricted stock units 26,100,000 21,400,000    
Restricted Stock Units (RSUs) | Minimum
        
Stockholders Equity [Line Items]        
Vesting period of awards 3 years      
Restricted Stock Units (RSUs) | Maximum
        
Stockholders Equity [Line Items]        
Vesting period of awards 5 years      
Stock Options
        
Stockholders Equity [Line Items]        
Recognized compensation expense $ 700,000 $ 700,000