Earnings (Loss) Per Share - 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, 2019	Nov. 30, 2018	Nov. 30, 2019	Nov. 30, 2018
Earnings Per Share, Basic and Diluted [Abstract]
Net income (loss) attributable to Class A and Common Shares	$ 70.9	$ 71.4	$ 12.5	$ 10.3
Weighted average Shares of Class A Stock and Common Stock outstanding for basic earnings (loss) per share	34.8	35.2	34.8	35.2
Dilutive effect of Class A Stock and Common Stock potentially issuable pursuant to stock-based compensation plans	0.3	0.7	0.4	0.6
Adjusted weighted average Shares of Class A Stock and Common Stock outstanding for diluted earnings (loss) per share (in millions)	35.1	35.9	35.2	35.8
Earnings (loss) per share of Class A Stock and Common Stock:
Basic (in Dollars per share)	$ 2.04	$ 2.03	$ 0.36	$ 0.29
Diluted (in Dollars per share)	$ 2.02	$ 1.99	$ 0.35	$ 0.29