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Weighted Average Assumptions Used to Estimate Fair Value of Stock Appreciation Right's at Date of Grant (Detail) - Stock Appreciation Rights (SARs)
12 Months Ended
Jan. 31, 2016
Jan. 31, 2015
Jan. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expected life, in years 0 years 0 years 5 years 7 months 6 days
Risk-free interest rate     1.00%
Volatility     46.00%
Dividend rate 0.00% 0.00% 0.00%