Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	May 31, 2023	May 31, 2022	May 31, 2021
Earnings per Share
Effect to the participating securities as result of net loss	$ 0.0
Basic and Diluted EPS:
Income from continuing operations	89.8	$ 78.5	$ 46.3
Less income attributable to participating shares	(1.1)	(0.6)	(0.4)
Income from continuing operations attributable to common shareholders	88.7	77.9	45.9
Income (Loss) from discontinued operations, net of tax	0.4	0.2	(10.5)
Net income attributable to common stockholders for earnings per share, Basic	89.1	78.1	35.4
Net income attributable to common stockholders for earnings per share, Diluted	$ 89.1	$ 78.1	$ 35.4
Weighted Average Shares:
Weighted average common shares outstanding - basic	34,700,000	35,600,000	35,000,000.0
Additional shares from the assumed exercise of stock options	400,000	400,000	300,000
Weighted average common shares outstanding - diluted	35,100,000	36,000,000.0	35,300,000
Earnings per share - basic:
Earnings from continuing operations	$ 2.55	$ 2.19	$ 1.31
Income (Loss) from discontinued operations	0.01	0.01	(0.30)
Earnings (Loss) per share - basic	2.56	2.20	1.01
Earnings per share - diluted:
Earnings from continuing operations	2.52	2.16	1.30
Income (Loss) from discontinued operations	0.01	0.01	(0.30)
Earnings (Loss) per share - diluted	$ 2.53	$ 2.17	$ 1.00
Antidilutive shares excluded from the computation of diluted earnings per share (in shares)	197,300	229,800	1,054,400