Quarterly report pursuant to Section 13 or 15(d)

Basic and Diluted Earnings Per Share (Details Textual)

v3.3.0.814
Basic and Diluted Earnings Per Share (Details Textual) - USD ($)
shares in Millions, $ in Millions
3 Months Ended
Aug. 31, 2015
Aug. 31, 2014
May. 31, 2014
Equity, Class of Treasury Stock [Line Items]      
Stock repurchased and retired during period, Shares 1.3 0.9  
Stock repurchased and retired during period, Value $ 62.9 $ 37.5  
Stock repurchase program, Authorized amount     $ 350.0
Common stock issued in connection with the exercise or vesting of stock-based awards 0.7 0.7