Share-Based Compensation - Share-based Compensation Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 12.4	$ 17.4	$ 22.9
Employee Share Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	0.2	0.3	0.1
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	3.3	5.3	5.5
Performance-based RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	5.7	7.0	12.0
Time-based RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	2.1	3.8	4.2
Director share awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 1.1	1.0	1.1
Discontinued Operations, Held-for-sale
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense		$ 0.1	$ 5.4