Restructuring - Summary of Employee Severance and Benefit Costs (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Aug. 31, 2012	Aug. 31, 2011
Restructuring Accrual:
Balance at May 31, 2012 and 2011 respectively	$ 7.9	$ 5.9
Costs incurred and charged to expense	1.0	8.2
Costs paid or otherwise settled	(0.3)	(2.2)
Non-cash adjustments		0.2	[1]
Balance at August 31, 2012 and 2011 respectively	$ 8.6	$ 12.1

[1] Primarily related to foreign currency fluctuations.