Revenues - Allowance for Credit Losses (Details) - USD ($) $ in Millions	3 Months Ended
	Aug. 31, 2021	Aug. 31, 2020
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	$ 21.4
Provision for losses on accounts receivable	1.6	$ 1.4
Write-offs and other	(1.2)
Accounts Receivable, Allowance for Credit Loss, Ending Balance	$ 21.8