Capital Stock and Stock-Based Awards (Details) (USD $)	12 Months Ended		1 Months Ended			12 Months Ended		49 Months Ended				12 Months Ended			12 Months Ended
	May 31, 2014	May 31, 2013	Sep. 30, 2013 Amended 2007 Directors Plan [Member]	May 31, 2014 1995 Plan [Member]	May 31, 2014 2001 Plan [Member]	May 31, 2014 Plan 2011 [Member]	May 31, 2014 1997 Directors’ Plan [Member]	Sep. 30, 2011 2007 Directors’ Plan [Member]	May 31, 2014 2007 Directors’ Plan [Member]	Sep. 30, 2007 2007 Directors’ Plan [Member]	Sep. 30, 2013 Employee Stock Option [Member] Amended 2007 Directors Plan [Member]	May 31, 2014 Restricted Stock Units (RSUs) [Member]	Sep. 30, 2013 Restricted Stock Units (RSUs) [Member] Amended 2007 Directors Plan [Member]	May 31, 2014 Class A Stock Options [Member]	May 31, 2014 Employee Stock Purchase Plan [Member]	May 31, 2014 Management Stock Purchase Plan [Member]	May 31, 2013 Management Stock Purchase Plan [Member]	May 31, 2012 Management Stock Purchase Plan [Member]	May 31, 2014 Stock Units And Restricted Stock Units [Member]
Capital Stock and Stock-Based Awards (Details) [Line Items]
Preferred stock issued	0	0
Options outstanding (Shares)	4,355,367	4,185,480		161,500	1,135,360	1,300,640	96,000		162,867					1,499,000
Options granted (Shares)	778,434		24,714			753,720
Weighted average exercise price of options granted (in Dollars per share)	$ 30.12		$ 30.56			$ 30.11
Common Stock Remaining Authorized Under EmployeeS tock Purchase Plan						464,873			274,391					0	161,910	331,453
Options granted per grantee							6,000
Non-qualified stock options outstanding										3,000
Restricted stock outstanding			12,366					1,200
Non qualified stock options to purchase (in Dollars)			$ 70,000
Non qualified stock options to purchase, Portion											40.00%		60.00%
Stock option compensation cost not yet recognized	3,300,000											2,500,000				100,000
Future period of stock option expense recognition	2 years 3 months 18 days											1 year 10 months 24 days				1 year 2 months 24 days
Common stock issued from conversion of RSUs												121,860
Deferred rate for annual cash bonus payment																100.00%
Quarterly basis discount rate of common stock on closing price															15.00%	25.00%
Fair value of shares vested																	$ 6,400,000	$ 6,000,000	$ 5,000,000