Income Taxes - Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Millions	May 31, 2025	May 31, 2024
Deferred tax assets
Accounts receivable	$ 1.9	$ 1.8
Inventories	2.8	2.8
Accrued expenses	7.1	9.2
Net operating loss carry forwards	4.5	2.8
Stock-based compensation	2.5	1.9
Operating lease - liability	4.2	4.4
Derivative contracts	0.0	0.2
Other	2.4	1.5
Deferred tax assets before valuation allowance	25.4	24.6
Less: Valuation allowance	0.0	0.0
Total deferred tax assets	25.4	24.6
Deferred tax liabilities
Property, plant and equipment	(28.2)	(28.7)
Investment in affiliated company, principally due to undistributed earnings	(8.7)	(10.5)
Operating lease - ROU assets	(3.8)	(4.2)
Prepaid expenses	(0.8)	0.0
Derivative contracts	(0.4)	0.0
Other	(0.7)	(0.6)
Total deferred tax liability	(42.6)	(44.0)
Net deferred tax asset (liability)	$ (17.2)	$ (19.4)