Earnings (Loss) Per Share (Detail) - Schedule of Calculation of Numerator and Denominator in Earnings Per Share (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended				9 Months Ended
	Feb. 29, 2012		Feb. 28, 2011		Feb. 29, 2012	Feb. 28, 2011
Earnings (loss) from continuing operations attributable to Class A and Common Shares (in Dollars)	$ (9.9)		$ (23.9)		$ 48.0	$ 19.0
Earnings (loss) from discontinued operations attributable to Class A and Common Shares, net of tax (in Dollars)	(0.4)		(1.1)		(2.9)	(4.6)
Net income (loss) attributable to Class A and Common Shares (in Dollars)	$ (10.3)		$ (25.0)		$ 45.1	$ 14.4
Weighted average Shares of Class A Stock and Common Stock outstanding for basic earnings (loss) per share (in millions) (in Shares)	31.1		30.9		31.1	33.8
Dilutive effect of Class A Stock and Common Stock potentially issuable pursuant to stock-based compensation plans (in millions) (in Shares)		[1]		[1]	0.5	0.5
Adjusted weighted average Shares of Class A Stock and Common Stock outstanding for diluted earnings (loss) per share (in millions) (in Shares)	31.1		30.9		31.6	34.3
Basic earnings (loss) per share:
Earnings (loss) from continuing operations	$ (0.32)		$ (0.77)		$ 1.54	$ 0.56
Earnings (loss) from discontinued operations, net of tax	$ (0.01)		$ (0.04)		$ (0.09)	$ (0.13)
Net income (loss)	$ (0.33)		$ (0.81)		$ 1.45	$ 0.43
Diluted earnings (loss) per share:
Earnings (loss) from continuing operations	$ (0.32)		$ (0.77)		$ 1.52	$ 0.55
Earnings (loss) from discontinued operations, net of tax	$ (0.01)		$ (0.04)		$ (0.09)	$ (0.13)
Net income (loss)	$ (0.33)		$ (0.81)		$ 1.43	$ 0.42

[1] In the three months ended February 29, 2012 and February 28, 2011, the Company experienced a loss from continuing operations and therefore did not report any dilutive share impact.