Employee Benefit Plans - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	May 31, 2022	May 31, 2021	May 31, 2020	Feb. 28, 2021
Employee Benefit Plans (Details) [Line Items]
Reduction in benefit obligation				$ 7.6
Amount recognized in Accumulated comprehensive income (loss) net of tax				$ 7.6
Remaining life of plan	12 years
Percentage of federal subsidy to sponsors of retiree health care benefit plans	28.00%
Cumulative reduction of its accumulated post-retirement benefit obligation	$ 0.2	$ 0.2	$ 1.2
Defined benefit plans tax expense recognized in AOCI	2.2	(2.0)	(0.1)
Estimated employer contributions in 2015	1.2
Contribution to retirement plan	7.2	6.0	6.7
Annuities | Level 3
Employee Benefit Plans (Details) [Line Items]
Fair value of annuities	4.2	6.0
U.K. | Pension Plans
Employee Benefit Plans (Details) [Line Items]
Reduction in benefit obligation	$ 31.9	$ 47.0	$ 41.7
Expected long-term return on plan assets	3.10%	2.20%	3.10%
U.S. | Other Postretirement Benefits
Employee Benefit Plans (Details) [Line Items]
Reduction in benefit obligation	$ 9.4	$ 12.1	$ 20.8
Expected long-term return on plan assets	0.00%	0.00%	0.00%