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Share-Based Compensation (Assumptions Used To Estimate Fair Value Of Stock Options) (Details)
12 Months Ended
Jan. 31, 2012
years
Jan. 31, 2011
years
Jan. 31, 2010
years
Stock Options [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expected life, in years 3.5 4.3 4.2
Risk-free interest rate 0.90% 1.80% 2.00%
Volatility 50.00% 49.90% 51.40%
Dividend rate         
Stock Appreciation Rights [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expected life, in years 4.8 5.3  
Risk-free interest rate 0.80% 1.60%  
Volatility 48.80% 47.90%  
Dividend rate