Stock Based Compensation (Expense Included in Selling, General and Administrative Expenses Related to Stock Options and Restricted Stock Awards) (Detail) (Selling, General and Administrative Expenses [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 26, 2014	Dec. 27, 2013	Dec. 28, 2012
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 12.4	$ 9.9	$ 10.3
Stock Options [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	5.2	6.8	8.4
RSUs and PSUs
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	6.5	2.4	1.2
Restricted Stock [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 0.7	$ 0.7	$ 0.7