Severance and Exit Costs (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
	Nov. 30, 2011	Nov. 30, 2011	May 31, 2011	Nov. 30, 2010	May 31, 2010
Severance Expense		$ 6.8
Accrued Severance Cost	2.4	2.4	1.9	0.9	3.4
Loss On Leases	$ 6.2	$ 6.2