Revenue Recognition - Contract Assets and Liabilities and Remaining Performance Obligations (Details) - USD ($) $ in Millions	3 Months Ended
	Aug. 31, 2020	Aug. 31, 2019	May 31, 2020
Contract Assets and Liabilities
Contract assets - current	$ 45.2		$ 49.3
Contract assets - non-current	21.5		22.4
Contract liabilities:
Deferred revenue - current	(15.2)		(11.2)
Deferred revenue on long-term contracts	(70.2)		(88.0)
Net contract liabilities	(18.7)		$ (27.5)
Change in contract assets - current	(4.1)
Change in contract assets - non-current	(0.9)
Change in contract liabilities - current	(4.0)
Change in contract liabilities - non-current	17.8
Change in net contract assets (liabilities)	8.8
Charge related to terminiation of PBH customer contract	2.2
PBH forward loss reserve	3.5
Change in Contract with Customer, Liability
Deferred revenue at beginning of period	(99.2)	$ (96.4)
Revenue deferred	(72.2)	(86.6)
Revenue recognized	88.5	101.0
Other	(2.5)	(4.3)
Deferred revenue at end of period	(85.4)	$ (86.3)
Remaining Performance Obligations
Remaining performance obligation	1,000.0
Accrued liabilities
Contract liabilities:
PBH forward loss reserve	1.6
Other liabilities
Contract liabilities:
PBH forward loss reserve	$ 1.9
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-09-01
Remaining Performance Obligations
Revenue, Remaining Performance Obligation, Percentage	60.00%
Expected timing of satisfaction of remaining performance obligation	12 months