Derivative Instruments And Hedging Activities (Schedule Of Derivatives Designated As Cash Flow Hedging Instruments) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Nov. 30, 2011	Nov. 30, 2010	Nov. 30, 2011	Nov. 30, 2010
Derivative [Line Items]
Income (Loss) Recognized in Other Comprehensive Income (Effective Portion)	$ (450)	$ (659)	$ (2,296)	$ (5,469)
Income (Loss) Reclassified from Accumulated Other Comprehensive Income (Effective Portion)	(1,214)	(984)	(263)	(1,836)
Interest Rate Contracts [Member]
Derivative [Line Items]
Income (Loss) Recognized in Other Comprehensive Income (Effective Portion)	257	(220)	(1,873)	(4,708)
Interest Rate Contracts [Member] | Interest Expense [Member]
Derivative [Line Items]
Income (Loss) Reclassified from Accumulated Other Comprehensive Income (Effective Portion)	(928)	(971)	(1,998)	(1,965)
Commodity Contracts [Member]
Derivative [Line Items]
Income (Loss) Recognized in Other Comprehensive Income (Effective Portion)	(707)	(439)	(423)	(761)
Commodity Contracts [Member] | Cost Of Goods Sold [Member]
Derivative [Line Items]
Income (Loss) Reclassified from Accumulated Other Comprehensive Income (Effective Portion)	$ (286)	$ (13)	$ 1,735	$ 129