Accumulated Other Comprehensive Income (Loss) - Schedule of AOCI Activity (Details) - USD ($) $ in Millions	3 Months Ended
	Aug. 31, 2022	Aug. 31, 2021	May 31, 2022	May 31, 2021
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	$ 1,166.3	$ 1,149.6	$ 1,218.4	$ 1,182.3
Other comprehensive income (loss) before reclassifications	(9.6)	(5.8)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, Tax	0.0	0.0
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, after Tax	(0.1)	(0.2)
Amortization of prior service (credit) cost (net of tax of $0.1)	(0.1)	(0.1)
Other comprehensive income (loss)	(9.6)	(5.7)
Ending balance	1,166.3	1,149.6	1,218.4	1,182.3
Amortization of prior service credit, Tax	0.1	0.1
Accumulated other comprehensive income (loss)	(55.0)	(40.4)	(45.4)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(55.0)	(40.4)	(45.4)	(34.7)
Ending balance	(55.0)	(40.4)	(45.4)	(34.7)
Accumulated other comprehensive income (loss)	(55.0)	(40.4)	(45.4)	(34.7)
Foreign currency translation adjustments
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Other comprehensive income (loss) before reclassifications	(9.6)	(5.8)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, after Tax	0.0	0.0
Amortization of prior service (credit) cost (net of tax of $0.1)	0.0	0.0
Other comprehensive income (loss)	(9.6)	(5.8)
Accumulated other comprehensive income (loss)	(54.2)	(35.9)	(44.6)	(30.1)
Retirement benefit plans
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Other comprehensive income (loss) before reclassifications	0.0	0.0
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, after Tax	(0.1)	(0.2)
Amortization of prior service (credit) cost (net of tax of $0.1)	(0.1)	(0.1)
Other comprehensive income (loss)	0.0	0.1
Accumulated other comprehensive income (loss)	$ (0.8)	$ (4.5)	$ (0.8)	$ (4.6)