- Schedule of Earnings Per Share, Basic and Diluted (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Nov. 30, 2017	Nov. 30, 2016	Nov. 30, 2017	Nov. 30, 2016
Earnings Per Share, Basic and Diluted [Abstract]
Earnings (loss) from continuing operations attributable to Class A and Common Shares	$ 57.0	$ 67.8	$ (6.6)	$ 28.3
Earnings (loss) from discontinued operations attributable to Class A and Common Shares, net of tax	0.0	0.0	0.0	(0.1)
Net income (loss) attributable to Class A and Common Shares	$ 57.0	$ 67.8	$ (6.6)	$ 28.2
Weighted average Shares of Class A Stock and Common Stock outstanding for basic earnings (loss) per share (in millions)	35.0	34.5	35.1	34.5
Dilutive effect of Class A Stock and Common Stock potentially issuable pursuant to stock-based compensation plans (in millions)	0.6	0.7	0.0	0.7
Adjusted weighted average Shares of Class A Stock and Common Stock outstanding for diluted earnings (loss) per share (in millions)	35.6	35.2	35.1	35.2
Basic earnings (loss) per share:
Earnings (loss) from continuing operations (in Dollars per share)	$ 1.63	$ 1.96	$ (0.19)	$ 0.82
Earnings (loss) from discontinued operations, net of tax (in Dollars per share)	0.00	0.00	0.00	0.00
Net income (loss) (in Dollars per share)	1.63	1.96	(0.19)	0.82
Diluted earnings (loss) per share:
Earnings (loss) from continuing operations (in Dollars per share)	1.60	1.92	(0.19)	0.81
Earnings (loss) from discontinued operations, net of tax (in Dollars per share)	0.00	0.00	0.00	(0.01)
Net income (loss) (in Dollars per share)	$ 1.60	$ 1.92	$ (0.19)	$ 0.80