Severance and Exit Costs (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended		12 Months Ended
	Nov. 30, 2012	Nov. 30, 2011	May 31, 2012	May 31, 2011
Severance	$ 2.1	$ 8.3	$ 14.9
Accrued Severance Cost	$ 1.9	$ 2.4	$ 2.7	$ 1.9