Share-based Compensation - Share-based Compensation Expense (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 29, 2018	Dec. 30, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 17.4	$ 22.9	$ 9.4
Employee Share Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	0.3	0.1	0.2
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	5.3	5.5	3.7
Performance-based RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	7.0	12.0	1.3
Time-based RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	3.8	4.2	3.3
Director share awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense		1.1	0.9
Discontinued Operations, Held-for-sale
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 0.1	$ 5.4	$ 2.4