XML 51 R34.htm IDEA: XBRL DOCUMENT  v2.3.0.11
Shareholder's Equity (Details) (USD $)
3 Months Ended 6 Months Ended
Jul. 31, 2011
Jul. 31, 2010
Jul. 31, 2011
Jul. 31, 2010
Jan. 31, 2011
Nov. 16, 2010
Feb. 28, 2006
Common shares authorized for repurchase, shares           10,000,000 8,000,000
Average cost per share $ 28.76 $ 33.74 $ 30.14 $ 33.74      
Stock repurchased and retired during period, common shares 2,340,330 2,015,180 7,165,199 2,015,180      
Stock repurchased and retired during period, value $ 67,319,000 $ 68,002,000 $ 215,993,000 $ 68,002,000      
Remaining common shares available for repurchase 3,326,354   3,326,354        
Additional paid-in-capital 0 138,413,000 0 138,413,000 27,603,000    
Retained earnings reduction related to shares repurchased 179,543,000   179,543,000        
From An Employee To Meet A Minimum Statutory Tax Withholding Requirement [Member]
             
Stock repurchased and retired during period, common shares   112,770   112,770      
Stock repurchased and retired during period, value   $ 3,986,000   $ 3,986,000