Employee Benefit Plans (Details) - Schedule Of Amounts Recognized In Balance Sheet - USD ($) $ in Millions	May 31, 2018	May 31, 2017
Other Postretirement Benefits [Member]
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract]
Current liabilities	$ (2.2)	$ (2.1)
Non-current liabilities	(24.6)	(26.7)
Net funded balance	(26.8)	(28.8)
U.S. [Member] | Pension Plans [Member]
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract]
Current liabilities	0.0	0.0
Non-current liabilities	0.0	0.0
Net funded balance	1.6	4.7
U.K. [Member] | Pension Plans [Member]
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract]
Current liabilities	0.0	0.0
Non-current liabilities	(9.2)	(12.5)
Net funded balance	(9.2)	(12.5)
Current Assets [Member] | Other Postretirement Benefits [Member]
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract]
Plan assets	0.0	0.0
Current Assets [Member] | U.S. [Member] | Pension Plans [Member]
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract]
Plan assets	1.6	4.7
Current Assets [Member] | U.K. [Member] | Pension Plans [Member]
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract]
Plan assets	0.0	0.0
Noncurrent Assets [Member] | Other Postretirement Benefits [Member]
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract]
Plan assets	0.0	0.0
Noncurrent Assets [Member] | U.S. [Member] | Pension Plans [Member]
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract]
Plan assets	0.0	0.0
Noncurrent Assets [Member] | U.K. [Member] | Pension Plans [Member]
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract]
Plan assets	$ 0.0	$ 0.0