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Shareholders' Equity - Stock Based Compensation - Additional Information (Detail) - shares
shares in Millions
9 Months Ended
Oct. 31, 2015
Jun. 04, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Maximum number of shares of the Company's common stock that was available for award grants under the Performance Plan 5.5 7.0
Stock-based awards vesting period 1 year  
Period in which stock option expires under condition 3 months  
Maximum [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Maximum term of options and stock appreciation rights under the Performance Plan 4 years  
Period in which stock option expires under condition one 10 years  
Minimum [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Maximum term of options and stock appreciation rights under the Performance Plan 3 years  
Period in which stock option expires under condition one 7 years