Leases (Details) - USD ($) $ in Millions	12 Months Ended
	May 31, 2017	May 31, 2016	May 31, 2015
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Operating leases minimum payments due, due in year one	$ 43.8
Operating leases minimum payments due, due in two years	35.9
Operating leases minimum payments due, due in three years	28.5
Operating leases minimum payments due, due in four years	22.3
Operating leases minimum payments due, due in five years	17.0
Operating leases minimum payments due, due thereafter	28.5
Continuing Operations
Operating Leased Assets [Line Items]
Operating lease rent expense	$ 49.6	$ 40.8	$ 34.2
Minimum
Operating Leased Assets [Line Items]
Operating leases renewal option period	1 year
Maximum
Operating Leased Assets [Line Items]
Operating leases renewal option period	10 years