Income Taxes - Activity Within the Tax Valuation Allowance (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 30, 2018	Dec. 31, 2017	Jan. 01, 2017
Increase (Decrease) in Valuation Allowance [Roll Forward]
Beginning balance	$ 5.2	$ 4.1	$ 4.2
Increase in valuation allowance	0.0	1.1	0.0
Decrease in valuation allowance	(0.4)	0.0	(0.1)
Ending balance	$ 4.8	$ 5.2	$ 4.1