Components of Net Periodic Benefit (Credit) Cost (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 28, 2012	Dec. 30, 2011	Dec. 31, 2010
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 0.7	$ 0.7	$ 0.7
Interest cost	0.6	0.6	0.5
Expected return on assets	(0.6)	(0.6)	(0.6)
Amortization of actuarial gain	(0.2)	(0.3)	(0.3)
Amortization of unrecognized prior service cost	0.1	0.1	0.1
Net periodic postretirement benefit cost	0.6	0.5	0.4
Curtailment	(0.3)	(0.7)
Total (credit) cost for the year	$ 0.3	$ (0.2)	$ 0.4