Share-Based Compensation - Expenses (Details) - Selling, General and Administrative Expenses - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 25, 2020	Sep. 27, 2019	Sep. 25, 2020	Sep. 27, 2019
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 1.6	$ 0.9	$ 6.2	$ 7.0
RSUs/PSUs
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	1.6	0.9	5.9	6.0
RSAs
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 0.0	$ 0.0	$ 0.3	$ 1.0