XML 49 R38.htm IDEA: XBRL DOCUMENT v3.5.0.2
Shareholders' Equity - Additional Information (Detail) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jul. 31, 2015
Jul. 31, 2016
Jul. 31, 2015
Feb. 23, 2015
May 27, 2014
Equity, Class of Treasury Stock [Line Items]          
Common shares authorized for repurchase, shares       20,000,000 10,000,000
Remaining common shares authorized for repurchase, shares   6,995,059      
Stock repurchased and retired during period, common shares 6,635,164 324,700 7,037,141    
Stock repurchased and retired during period, total cost $ 236,312 $ 10,704 $ 253,618    
Employee Stock          
Equity, Class of Treasury Stock [Line Items]          
Stock repurchased and retired during period, common shares   0 181,890    
Stock repurchased and retired during period, total cost     $ 8,017