Accumulated Other Comprehensive Income (Loss) - Schedule of AOCI Activity (Details) - USD ($) $ in Millions	12 Months Ended
	May 31, 2024	May 31, 2023	May 31, 2022
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	$ (55.8)	$ (45.4)
Other comprehensive income (loss) before reclassifications	2.6	(10.3)
Other comprehensive income (loss)	3.3	(10.4)
Ending balance	(52.5)	(55.8)	$ (45.4)
Pension and postretirement adjustments, tax portion	2.0	2.2	2.2
Foreign currency translation adjustments
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(50.0)	(44.6)
Other comprehensive income (loss) before reclassifications	3.1	(5.4)
Amortization of net actuarial loss	0.0	0.0
Amortization of prior service (credit) cost	0.0	0.0
Other comprehensive income (loss)	3.1	(5.4)
Ending balance	(46.9)	(50.0)	(44.6)
Recognized net actuarial loss
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Amortization of net actuarial loss	1.3	0.5
Amortization of prior service (credit) cost	(0.6)	(0.6)
Pension Plans
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(12.4)	(7.4)
Other comprehensive income (loss) before reclassifications	(0.7)	(5.5)
Amortization of net actuarial loss	1.3	0.5	0.9
Other comprehensive income (loss)	0.6	(5.0)
Ending balance	(11.8)	(12.4)	(7.4)
Pension Plans | Recognized net actuarial loss
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Amortization of net actuarial loss	1.3	0.5
Amortization of prior service (credit) cost	0.0	0.0
Postretirement Benefits
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	6.6	6.6
Other comprehensive income (loss) before reclassifications	0.2	0.6
Amortization of net actuarial loss	(0.6)	(0.6)	(0.6)
Other comprehensive income (loss)	(0.4)	0.0
Ending balance	6.2	6.6	$ 6.6
Postretirement Benefits | Recognized net actuarial loss
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Amortization of net actuarial loss	0.0	0.0
Amortization of prior service (credit) cost	$ (0.6)	$ (0.6)