Restructuring And Other Expense (Schedule Of Progression Of Liabilities Created As Part Of The Plan, Combined With A Reconciliation To The Restructuring And Other Expense) (Details) (USD $) In Thousands	3 Months Ended
	Aug. 31, 2011	Aug. 31, 2010
5/31/2011 Liability	$ 7,629
Expense	4,918
Payments	(4,889)
Adjustments	2,009
8/31/2011 Liability	9,667
Joint venture transactions	(3,215)
Total	1,703	1,064
Facility exit and other costs [Member]
5/31/2011 Liability	409
Expense	5,212
Payments	(3,513)
Adjustments	17
8/31/2011 Liability	2,125
Early Retirement And Severance [Member]
5/31/2011 Liability	7,220
Expense	(294)
Payments	(1,376)
Adjustments	1,992
8/31/2011 Liability	$ 7,542