Revenues - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
Aug. 31, 2018	May 31, 2018	Aug. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Retained earnings	$ 952.1	$ 1,065.2	$ 1,022.2
Returns liability	45.4	0.0	$ 0.0
Return asset	3.5
Deferred revenue recognized	$ 31.9
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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Amount of liability for consideration received or receivable from customer which is not included in transaction price, when consideration is expected to be refunded to customer, classified as current.

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