Retirement Plans (Details) - USD ($) $ in Millions	3 Months Ended
	Aug. 26, 2018	Aug. 27, 2017
Defined Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Interest cost	$ 2.4	$ 2.1
Expected return on plan assets	(2.8)	(3.0)
Recognized net actuarial loss	0.6	0.7
Net periodic benefit (credit) cost	0.2	(0.2)
Postretirement Benefit Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Interest cost	0.2	0.2
Amortization of unrecognized prior service credit	(1.2)	(1.2)
Recognized net actuarial loss	0.4	0.4
Net periodic benefit (credit) cost	$ (0.6)	$ (0.6)