Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	12 Months Ended
	May 31, 2023	May 31, 2022	May 31, 2021
Accumulated Other Comprehensive Loss
Balance at beginning of the period	$ (19.6)	$ (18.3)	$ (44.6)
Other comprehensive income (loss) before reclassifications	(2.2)	(2.1)	10.3
Amounts reclassified from AOCL	(1.7)	0.8	16.0
Total other comprehensive income (loss)	(3.9)	(1.3)	26.3
Balance at end of the period	(23.5)	(19.6)	(18.3)
Currency Translation Adjustments
Accumulated Other Comprehensive Loss
Balance at beginning of the period	(2.8)	3.9	(2.0)
Other comprehensive income (loss) before reclassifications	(2.9)	(6.7)	5.9
Amounts reclassified from AOCL	0.0
Total other comprehensive income (loss)	(2.9)	(6.7)	5.9
Balance at end of the period	(5.7)	(2.8)	3.9
Pensions Plans
Accumulated Other Comprehensive Loss
Balance at beginning of the period	(16.8)	(22.2)	(42.6)
Other comprehensive income (loss) before reclassifications	0.7	4.6	4.4
Amounts reclassified from AOCL	(1.7)	0.8	16.0
Total other comprehensive income (loss)	(1.0)	5.4	20.4
Balance at end of the period	$ (17.8)	$ (16.8)	$ (22.2)