Condensed Consolidated Statements of Changes in Equity (Unaudited) - USD ($) $ in Millions	Common Stock	Capital Surplus	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Loss	Total
Balance at May. 31, 2022	$ 45.3	$ 477.5	$ 820.4	$ (289.1)	$ (19.6)	$ 1,034.5
Increase (Decrease) in Stockholders' Equity
Net income (loss)			22.7			22.7
Stock option activity		1.0		1.5		2.5
Restricted stock activity		(1.7)		3.5		1.8
Repurchase of shares				(21.9)		(21.9)
Other comprehensive loss, net of tax					(3.1)	(3.1)
Balance at Aug. 31, 2022	45.3	476.8	843.1	(306.0)	(22.7)	1,036.5
Balance at May. 31, 2022	45.3	477.5	820.4	(289.1)	(19.6)	1,034.5
Increase (Decrease) in Stockholders' Equity
Net income (loss)						45.2
Other comprehensive loss, net of tax						(3.2)
Balance at Nov. 30, 2022	45.3	479.0	865.6	(331.8)	(22.8)	1,035.3
Balance at Aug. 31, 2022	45.3	476.8	843.1	(306.0)	(22.7)	1,036.5
Increase (Decrease) in Stockholders' Equity
Net income (loss)			22.5			22.5
Stock option activity		0.2		2.4		2.6
Restricted stock activity		2.0				2.0
Repurchase of shares				(28.2)		(28.2)
Other comprehensive loss, net of tax					(0.1)	(0.1)
Balance at Nov. 30, 2022	45.3	479.0	865.6	(331.8)	(22.8)	1,035.3
Balance at May. 31, 2023	45.3	484.5	910.6	(317.8)	(23.5)	1,099.1
Increase (Decrease) in Stockholders' Equity
Net income (loss)			(0.6)			(0.6)
Stock option activity		(0.3)		7.0		6.7
Restricted stock activity		(2.4)		3.7		1.3
Other comprehensive loss, net of tax					15.4	15.4
Balance at Aug. 31, 2023	45.3	481.8	910.0	(307.1)	(8.1)	1,121.9
Balance at May. 31, 2023	45.3	484.5	910.6	(317.8)	(23.5)	1,099.1
Increase (Decrease) in Stockholders' Equity
Net income (loss)						23.2
Other comprehensive loss, net of tax						15.0
Balance at Nov. 30, 2023	45.3	485.7	933.8	(300.8)	(8.5)	1,155.5
Balance at Aug. 31, 2023	45.3	481.8	910.0	(307.1)	(8.1)	1,121.9
Increase (Decrease) in Stockholders' Equity
Net income (loss)			23.8			23.8
Stock option activity		0.9		6.3		7.2
Restricted stock activity		3.0				3.0
Other comprehensive loss, net of tax					(0.4)	(0.4)
Balance at Nov. 30, 2023	$ 45.3	$ 485.7	$ 933.8	$ (300.8)	$ (8.5)	$ 1,155.5