XML 42 R36.htm IDEA: XBRL DOCUMENT v2.4.0.8
Net Income per Common Share - Additional Information (Detail)
3 Months Ended 9 Months Ended
Oct. 31, 2013
Oct. 31, 2012
Oct. 31, 2013
Oct. 31, 2012
Earnings Per Share [Line Items]        
Anti-dilutive common shares 204,500 2,904,808 101,500 3,219,200
Performance Stock Units
       
Earnings Per Share [Line Items]        
Anti-dilutive common shares     1,751,100 1,952,158