Earnings (Loss) Per Share (Details) - Schedule of Earnings Per Share, Basic and Diluted - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	May 31, 2018	May 31, 2017	May 31, 2016
Earnings Per Share [Abstract]
Earnings (loss) from continuing operations	$ (5.0)	$ 52.4	$ 43.9
Earnings (loss) from discontinued operations attributable to Class A and Common Shares, net of tax	0.0	(0.2)	(3.5)
Net income (loss) attributable to Class A and Common Shares	$ (5.0)	$ 52.2	$ 40.4
Weighted average Shares of Class A Stock and Common Stock outstanding for basic earnings (loss) per share (in millions)	35.0	34.7	34.1
Dilutive effect of Class A Stock and Common Stock potentially issuable pursuant to stock-based compensation plans (in millions)	0.0	0.7	0.8
Adjusted weighted average Shares of Class A Stock and Common Stock outstanding for diluted earnings (loss) per share (in millions)	35.0	35.4	34.9
Basic:
Earnings (loss) from continuing operations (in Dollars per share)	$ (0.14)	$ 1.51	$ 1.29
Earnings (loss) from discontinued operations (in Dollars per share)	0.00	0.00	(0.11)
Net income (loss) (in Dollars per share)	(0.14)	1.51	1.18
Diluted:
Earnings (loss) from continuing operations (in Dollars per share)	(0.14)	1.48	1.26
Earnings (loss) from discontinued operations (in Dollars per share)	0.00	(0.01)	(0.10)
Net income (loss) (in Dollars per share)	$ (0.14)	$ 1.47	$ 1.16