Summary of Compensation Cost Relating to Unvested Awards (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 28, 2014
Equity Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized Compensation Cost for Unvested Awards	$ 0.3
Weighted Average Remaining Recognition Period	2 years 3 months 18 days
Deferred Stock Units (DSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized Compensation Cost for Unvested Awards	0.4
Weighted Average Remaining Recognition Period	1 year 10 months 24 days
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized Compensation Cost for Unvested Awards	49.9
Weighted Average Remaining Recognition Period	2 years 8 months 12 days
Performance Units (PUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized Compensation Cost for Unvested Awards	$ 6.5
Weighted Average Remaining Recognition Period	2 years