Goodwill and Other Intangibles (Detail) - Schedule of other intangible assets subject to amortization (USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended
	Aug. 31, 2012	Aug. 31, 2011	May 31, 2012
Begining balance	$ 14.7
Amortization expense	0.5	0.4
Total other intangibles subject to amortization	14.4	17.6
Customer Lists [Member]
Begining balance	4.3	0.7	0.7
Additions due to acquisition	0.1		3.8
Amortization expense	(0.2)	0	(0.2)
Foreign currency translation	0	0	0
Total other intangibles subject to amortization	4.2	0.7	4.3
Other Intangible Assets [Member]
Begining balance	10.4	17.3	17.3
Impairment charge			(5.4)
Amortization expense	(0.3)	(0.4)	(1.4)
Other	0.1		(0.1)
Total other intangibles subject to amortization	$ 10.2	$ 16.9	$ 10.4