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Net Income (Loss) per Common Share - Additional Information (Detail) - $ / shares
3 Months Ended 6 Months Ended
Jul. 31, 2020
Jul. 31, 2019
Jul. 31, 2020
Jul. 31, 2019
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Anti-dilutive common shares 560,000 420,000   400,000
Anti-dilutive common shares exercise price, minimum $ 18.81 $ 28.47   $ 28.47
Anti-dilutive common shares exercise price, maximum $ 46.42 $ 46.42   $ 46.42
Performance Stock Units (PSUs)        
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Anti-dilutive common shares     706,794 780,264