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Share-Based Compensation - Additional Information (Detail) - USD ($)
12 Months Ended
Jan. 31, 2016
Jan. 31, 2015
Jan. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Assumed annualized forfeiture rate 5.00% 5.00% 5.00%
Tax benefit associated with share-based compensation expense $ 6,182,000 $ 6,367,000 $ 5,976,000
Tax benefit realized from share-based compensation $ 14,512,000 $ 5,813,000 $ 10,611,000
Common shares per PSU 100.00%    
Minimum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock options vesting period, maximum (in years) 7 years    
Maximum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock options vesting period, maximum (in years) 10 years    
Two Thousand Eight Stock Incentive Plan      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Common shares authorized 10,000,000    
Common shares available to grant 4,040,821    
Share based awards granted in previous years      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Assumed annualized forfeiture rate 5.00%    
Stock Options      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Compensation cost of stock options granted but not yet vested $ 286,000    
Weighted average period of recognition (in years) 3 months 18 days    
Stock Options | Minimum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock options vesting period, maximum (in years) 1 year    
Stock Options | Maximum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock options vesting period, maximum (in years) 3 years    
Stock Appreciation Rights (SARs)      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock options vesting period, maximum (in years) 5 years    
Compensation cost of stock options granted but not yet vested $ 379,000    
Weighted average period of recognition (in years) 1 year 7 months 6 days    
Awards granted 0 0  
Performance Stock Units      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock options vesting period, maximum (in years) 5 years    
Compensation cost of stock options granted but not yet vested $ 44,682,000    
Weighted average period of recognition (in years) 3 years    
Weighted average grant date fair value $ 18.94 $ 23.40 $ 25.13
Granted, Shares 1,471,000 163,336  
Vested, Shares 435,996    
Restricted Stock Units (RSUs)      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Compensation cost of stock options granted but not yet vested $ 0    
Weighted average grant date fair value $ 0   $ 39.06
Granted, Shares 0 0  
Vested, Shares 5,000   0
Restricted Stock Units (RSUs) | Minimum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock options vesting period, maximum (in years) 3 years    
Restricted Stock Units (RSUs) | Maximum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock options vesting period, maximum (in years) 5 years