Annual report pursuant to Section 13 and 15(d)

Income Taxes (Details Textuals)

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Income Taxes (Details Textuals) (USD $)
In Millions
12 Months Ended
May 31, 2011
May 31, 2010
Income Taxes (Textuals) [Abstract]    
Total reserve for uncertain tax positions $ 34.4 $ 27.5
Impact of uncertain tax position in company's effective income tax rate 29.2  
Total reserve for uncertain tax positions which included in long-term liabilities on the consolidated balance sheets $ 34.1 $ 27.4