Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Feb. 28, 2019	Aug. 31, 2018	Feb. 28, 2018	Feb. 28, 2019	Feb. 28, 2018	May 31, 2018
Income Tax Disclosure [Abstract]
Unrecognized tax benefits	$ 31.5			$ 31.5		$ 26.9
Provisional transition tax liability		$ 13.1				$ 9.8
Provisional income tax expense		$ 3.3
Measurement period adjustment - income tax benefit	3.1
Final transition tax liability	9.9			$ 9.9
Measurement period adjustment to deferred tax assets and liabilities - income tax expense	$ 0.4
Effective tax rate	20.10%		(69.50%)	19.30%	0.90%