Earnings (Loss) Per Share (Details) - Schedule of Earnings Per Share, Basic and Diluted (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Nov. 30, 2014	Nov. 30, 2013	Nov. 30, 2014	Nov. 30, 2013
Schedule of Earnings Per Share, Basic and Diluted [Abstract]
Earnings (loss) from continuing operations attributable to Class A and Common Shares (in Dollars)	$ 68.5	$ 58.2	$ 34.5	$ 28.1
Earnings (loss) from discontinued operations attributable to Class A and Common Shares, net of tax (in Dollars)	(0.1)	0	(0.2)	0.2
Net income (loss) attributable to Class A and Common Shares (in Dollars)	$ 68.4	$ 58.2	$ 34.3	$ 28.3
Weighted average Shares of Class A Stock and Common Stock outstanding for basic earnings (loss) per share (in millions) (in Shares)	32.7	31.9	32.5	31.8
Dilutive effect of Class A Stock and Common Stock potentially issuable pursuant to stock-based compensation plans (in millions) (in Shares)	0.6	0.4	0.7	0.6
Adjusted weighted average Shares of Class A Stock and Common Stock outstanding for diluted earnings (loss) per share (in millions) (in Shares)	33.3	32.3	33.2	32.4
Basic earnings (loss) per share:
Earnings (loss) from continuing operations	$ 2.10	$ 1.82	$ 1.06	$ 0.88
Earnings (loss) from discontinued operations, net of tax	$ (0.01)	$ 0.00	$ 0.000000	$ 0.01
Net income (loss) (in Dollars per share)	$ 2.09	$ 1.82	$ 1.06	$ 0.89
Diluted earnings (loss) per share:
Earnings (loss) from continuing operations	$ 2.06	$ 1.80	$ 1.04	$ 0.87
Earnings (loss) from discontinued operations, net of tax	$ (0.01)	$ 0.00	$ 0.000000	$ 0.01
Net income (loss) (in Dollars per share)	$ 2.05	$ 1.80	$ 1.04	$ 0.88