Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	May 31, 2022	May 31, 2021	May 31, 2020
Earnings Per Share
Effect to the participating securities as result of net loss	$ 0.0
Basic and Diluted EPS:
Income from continuing operations	78.5	$ 46.3	$ 24.8
Less income attributable to participating shares	(0.6)	(0.4)	(0.1)
Income from continuing operations attributable to common stockholders	77.9	45.9	24.7
Income (Loss) from discontinued operations attributable to common stockholders	0.2	(10.5)	(20.4)
Net income attributable to common stockholders for earnings per share	$ 78.1	$ 35.4	$ 4.3
Weighted Average Shares:
Weighted average common shares outstanding - basic	35,600,000	35,000,000.0	34,800,000
Additional shares from assumed exercise of stock options	400,000	300,000	200,000
Weighted average common shares outstanding - diluted	36,000,000.0	35,300,000	35,000,000.0
Earnings per share - basic:
Earnings from continuing operations	$ 2.19	$ 1.31	$ 0.71
Loss from discontinued operations	0.01	(0.30)	(0.59)
Earnings per share - basic	2.20	1.01	0.12
Earnings per share - diluted:
Earnings from continuing operations	2.16	1.30	0.71
Loss from discontinued operations	0.01	(0.30)	(0.58)
Earnings per share - diluted	$ 2.17	$ 1.00	$ 0.13
Antidilutive shares excluded from the computation of diluted earnings per share (in shares)	229,800	1,054,400	669,400