Accumulated Other Comprehensive Income (Loss) - Schedule of AOCI Activity (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Nov. 30, 2025	Nov. 30, 2024	Nov. 30, 2025	Nov. 30, 2024
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	$ 878.0	$ 957.3	$ 946.5	$ 1,018.1
Other comprehensive income (loss) before reclassifications	(3.8)	(11.9)	(0.3)	(3.7)
Amortization of net actuarial (gain) loss (net of tax of $0.0)	0.4	0.4	0.8	0.7
Amortization of prior service (credit) cost (net of tax of $0.0)	(0.2)	(0.2)	(0.3)	(0.3)
Other comprehensive income (loss)	(3.6)	(11.7)	0.2	(3.3)
Ending Balance	931.2	986.0	931.2	986.0
Reclassification adjustment from AOCI, tax	0.0	0.0	0.0	0.0
Amortization of prior service credit, tax	0.0	0.0	0.1	0.1
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(37.7)	(44.1)	(41.5)	(52.5)
Ending Balance	(41.3)	(55.8)	(41.3)	(55.8)
Foreign currency translation adjustments
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(32.5)	(38.7)	(36.0)	(46.9)
Other comprehensive income (loss) before reclassifications	(3.8)	(11.9)	(0.3)	(3.7)
Amortization of net actuarial (gain) loss (net of tax of $0.0)	0.0	0.0	0.0	0.0
Amortization of prior service (credit) cost (net of tax of $0.0)	0.0	0.0	0.0	0.0
Other comprehensive income (loss)	(3.8)	(11.9)	(0.3)	(3.7)
Ending Balance	(36.3)	(50.6)	(36.3)	(50.6)
Retirement benefit plans
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(5.2)	(5.4)	(5.5)	(5.6)
Other comprehensive income (loss) before reclassifications	0.0	0.0	0.0	0.0
Amortization of net actuarial (gain) loss (net of tax of $0.0)	0.4	0.4	0.8	0.7
Amortization of prior service (credit) cost (net of tax of $0.0)	(0.2)	(0.2)	(0.3)	(0.3)
Other comprehensive income (loss)	0.2	0.2	0.5	0.4
Ending Balance	$ (5.0)	$ (5.2)	$ (5.0)	$ (5.2)