Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Policies - Schedule of Anti-dilutive Securities Excluded from Computation of Earnings Per Share (Detail)

v3.19.1
Summary of Significant Accounting Policies - Schedule of Anti-dilutive Securities Excluded from Computation of Earnings Per Share (Detail) - shares
shares in Thousands
3 Months Ended
Apr. 30, 2019
Apr. 30, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Anti-dilutive potentially outstanding common shares 3,531 4,096
Stock Options [Member]    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Anti-dilutive potentially outstanding common shares 2,937 3,195
Restricted Stock Units [Member]    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Anti-dilutive potentially outstanding common shares 291 387
Deferred Stock Units [Member]    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Anti-dilutive potentially outstanding common shares 188 163
Performance Stock Units (PSUs) [Member]    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Anti-dilutive potentially outstanding common shares 115 351