Revenues - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Nov. 30, 2018	Nov. 30, 2018	May 31, 2018	Nov. 30, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Retained earnings	$ 1,018.4	$ 1,018.4	$ 1,065.2	$ 1,074.1
Returns liability	78.7	78.7	0.0	$ 0.0
Return asset	9.4	9.4
Deferred revenue recognized	$ 30.8	$ 62.7
Adjustments due to adoption \| ASU 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Retained earnings			(46.5)
Returns liability			$ 28.3

Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due.

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