Earnings (Loss) Per Share (Detail) - Schedule of Earnings Per Share, Basic and Diluted (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended				9 Months Ended
	Feb. 28, 2013		Feb. 29, 2012		Feb. 28, 2013	Feb. 29, 2012
Net income (loss) attributable to Class A and Common Shares (in Dollars)	$ (20.1)		$ (10.3)		$ 9.6	$ 45.4
Earnings (loss) from continuing operations attributable to Class A and Common Shares (in Dollars)	(20.1)		(9.9)		9.8	48.3
Earnings (loss) from discontinued operations attributable to Class A and Common Shares, net of tax (in Dollars)	0		(0.4)		(0.2)	(2.9)
Earnings attributable to participating securities (in Dollars)					$ 0.1	$ 0.3
Weighted average Shares of Class A Stock and Common Stock outstanding for basic earnings (loss) per share (in millions) (in Shares)	32.0		31.1		31.8	31.1
Dilutive effect of Class A Stock and Common Stock potentially issuable pursuant to stock-based compensation plans (in millions) (in Shares)		[1]		[1]	0.6	0.5
Adjusted weighted average Shares of Class A Stock and Common Stock outstanding for diluted earnings (loss) per share (in millions) (in Shares)	32.0		31.1		32.4	31.6
Potentially dilutive shares outstanding pursuant to stock-based compensation plans (in millions) (in Shares)	2.4		3.7		2.0	4.3
Basic earnings (loss) per share:
Earnings (loss) from continuing operations	$ (0.63)		$ (0.32)		$ 0.31	$ 1.54
Earnings (loss) from discontinued operations, net of tax	$ 0.00		$ (0.01)		$ (0.01)	$ (0.09)
Net income (loss)	$ (0.63)		$ (0.33)		$ 0.30	$ 1.45
Diluted earnings (loss) per share:
Earnings (loss) from continuing operations	$ (0.63)		$ (0.32)		$ 0.30	$ 1.52
Earnings (loss) from discontinued operations, net of tax	$ 0.00		$ (0.01)		$ (0.01)	$ (0.09)
Net income (loss)	$ (0.63)		$ (0.33)		$ 0.29	$ 1.43

[1] In the three months ended February 28, 2013 and February 29, 2012, the Company experienced a loss from continuing operations and therefore did not report any dilutive share impact.