Income Taxes - Deferred tax assets and liabilities (Details) - USD ($) $ in Millions	May 31, 2025	May 31, 2024
Deferred tax assets:
Operating lease liabilities	$ 25.4	$ 25.6
Employee and retirement benefits	8.9	9.0
State net operating losses	6.4	6.2
Other	8.2	6.9
Total deferred tax assets	48.9	47.7
Deferred tax liabilities:
Intangible assets	(32.2)	(24.9)
ROU operating lease assets	(25.8)	(26.5)
Tangible assets	(5.0)	(15.2)
Other	(4.3)	(5.0)
Total deferred tax liabilities	(67.3)	(71.6)
Net deferred tax liabilities	$ (18.4)	$ (23.9)