Restructuring (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended								6 Months Ended
	Nov. 30, 2014		Aug. 31, 2014		Nov. 30, 2013		Aug. 31, 2013		Nov. 30, 2014	Nov. 30, 2013
Restructuring and Related Activities [Abstract]
Employee severance costs	$ 3.2				$ 5.9				$ 5.0	$ 12.2
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	23.1		42.5		10.6		8.9		42.5	8.9
Costs incurred and charged to expense	3.2		1.8		5.9		6.3
Costs paid or otherwise settled	(2.5)		(21.0)		(3.9)		(5.3)
Non-cash adjustments	0	[1]	(0.2)	[1]	0.8	[1]	0.7	[1]
Restructuring reserve, ending balance	$ 23.8		$ 23.1		$ 13.4		$ 10.6		$ 23.8	$ 13.4

[1] Primarily related to foreign currency fluctuations.