Commitments and Contingencies (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	May 31, 2018	May 31, 2017	May 31, 2016
Commitments and Contingencies [Abstract]
Other current liabilities related to termination of license agreements	$ 34.8
Cost related to termination of license agreements, net of tax	24.7
Cost to acquire rights to client lists	30.0
Rent expense	39.9	$ 39.7	$ 39.8
Minimum future payment obligations under purchase orders and legally binding contractual arrangements	130.2
Commitments to purchase capital assets	$ 6.7