Summary of Significant Accounting Policies - Allowance for Doubtful Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	May 31, 2020	May 31, 2019	May 31, 2018	Jun. 01, 2019
Allowance for Doubtful Accounts
Other liabilities	$ 34.4	$ 28.3		$ 25.2
Balance, beginning of year	16.0	7.5	$ 4.9
Provision charged to operations	5.4	15.8	0.5
Recoveries, deductions for accounts written off and other reclassifications	0.7	(7.3)	2.1
Balance, end of year	22.1	16.0	$ 7.5
European airline customer
Allowance for Doubtful Accounts
Impairment of non-current contract assets		7.6
Other liabilities		1.5
Balance, beginning of year	$ 3.3
Provision charged to operations		12.4
Balance, end of year		$ 3.3