Retirement Plans (Schedule of Net Periodic Benefit Cost) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 25, 2020	Dec. 27, 2019
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 0.2	$ 0.2	$ 0.1
Interest cost	0.3	0.5	0.7
Amortization of net actuarial loss	0.9	0.7	0.5
Amortization of prior service cost (credit)	0.1	0.1	0.2
Net period benefit cost (credit)	1.5	1.5	1.5
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	0.0	0.0	0.0
Interest cost	0.7	1.2	1.6
Amortization of net actuarial loss	0.2	0.0	0.0
Amortization of prior service cost (credit)	(2.1)	(2.1)	(2.1)
Net period benefit cost (credit)	$ (1.2)	$ (0.9)	$ (0.5)