CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY Statement - USD ($) shares in Millions, $ in Millions	Total	Common Class	Common Class Common Class A	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Treasury Stock At Cost
Beginning balance at May. 31, 2024	$ 1,018.1	$ 0.4	$ 0.0	$ 604.6	$ (52.5)	$ 1,023.7	$ (558.1)
Balance (in shares) at Aug. 31, 2024		27.3	0.8
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(62.5)					(62.5)
Foreign currency translation adjustments	8.2				8.2
Pension and post-retirement adjustments (net of tax of $0.0)	0.2				0.2
Stock-based compensation	2.2			2.2
Proceeds pursuant to stock-based compensation plans	0.1			0.1
Purchases of treasury stock at cost (in shares)		(0.2)
Purchases of treasury stock at cost	(5.0)						(5.0)
Treasury stock issued pursuant to equity-based plans (in shares)		0.1
Treasury stock issued pursuant to equity-based plans	1.6			(0.6)			2.2
Dividends	(5.6)					(5.6)
Ending Balance at Aug. 31, 2024	957.3	$ 0.4	$ 0.0	606.3	(44.1)	955.6	(560.9)
Balance (in shares) at May. 31, 2024		27.4	0.8
Beginning balance at May. 31, 2024	1,018.1	$ 0.4	$ 0.0	604.6	(52.5)	1,023.7	(558.1)
Balance (in shares) at Nov. 30, 2024		27.3	0.8
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(13.7)
Foreign currency translation adjustments	(3.7)
Ending Balance at Nov. 30, 2024	986.0	$ 0.4	$ 0.0	603.5	(55.8)	998.7	(560.8)
Balance (in shares) at May. 31, 2024		27.4	0.8
Beginning balance at Aug. 31, 2024	957.3	$ 0.4	$ 0.0	606.3	(44.1)	955.6	(560.9)
Balance (in shares) at Nov. 30, 2024		27.3	0.8
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	48.8					48.8
Foreign currency translation adjustments	(11.9)				(11.9)
Pension and post-retirement adjustments (net of tax of $0.0)	0.2				0.2
Stock-based compensation	2.1			2.1
Proceeds pursuant to stock-based compensation plans	(0.5)			(0.5)
Purchases of treasury stock at cost (in shares)		(0.1)
Purchases of treasury stock at cost	(5.0)						(5.0)
Treasury stock issued pursuant to equity-based plans (in shares)		0.1
Treasury stock issued pursuant to equity-based plans	0.7			(4.4)			5.1
Dividends	(5.7)					(5.7)
Ending Balance at Nov. 30, 2024	986.0	$ 0.4	$ 0.0	603.5	(55.8)	998.7	(560.8)
Balance (in shares) at Aug. 31, 2024		27.3	0.8
Beginning balance at May. 31, 2025	946.5	$ 0.4	$ 0.0	607.1	(41.5)	999.7	(619.2)
Balance (in shares) at Aug. 31, 2025		24.3	0.8
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(71.1)					(71.1)
Foreign currency translation adjustments	3.5				3.5
Pension and post-retirement adjustments (net of tax of $0.0)	0.3				0.3
Stock-based compensation	1.9			1.9
Proceeds pursuant to stock-based compensation plans	0.5			0.5
Treasury stock issued pursuant to equity-based plans (in shares)		0.1
Treasury stock issued pursuant to equity-based plans	1.5			(1.6)			3.1
Dividends	(5.1)					(5.1)
Ending Balance at Aug. 31, 2025	878.0	$ 0.4	$ 0.0	607.9	(37.7)	923.5	(616.1)
Balance (in shares) at May. 31, 2025		24.2	0.8
Beginning balance at May. 31, 2025	946.5	$ 0.4	$ 0.0	607.1	(41.5)	999.7	(619.2)
Balance (in shares) at Nov. 30, 2025		24.6	0.8
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(15.2)
Foreign currency translation adjustments	(0.3)
Ending Balance at Nov. 30, 2025	931.2	$ 0.4	$ 0.0	604.1	(41.3)	974.2	(606.2)
Balance (in shares) at May. 31, 2025		24.2	0.8
Beginning balance at Aug. 31, 2025	878.0	$ 0.4	$ 0.0	607.9	(37.7)	923.5	(616.1)
Balance (in shares) at Nov. 30, 2025		24.6	0.8
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	55.9					55.9
Foreign currency translation adjustments	(3.8)				(3.8)
Pension and post-retirement adjustments (net of tax of $0.0)	0.2				0.2
Stock-based compensation	2.5			2.5
Proceeds pursuant to stock-based compensation plans	2.9			2.9
Treasury stock issued pursuant to equity-based plans (in shares)		0.3
Treasury stock issued pursuant to equity-based plans	0.7			(9.2)			9.9
Dividends	(5.2)					(5.2)
Ending Balance at Nov. 30, 2025	$ 931.2	$ 0.4	$ 0.0	$ 604.1	$ (41.3)	$ 974.2	$ (606.2)
Balance (in shares) at Aug. 31, 2025		24.3	0.8