Information of Benefit Obligations Plan Assets and Funded Status (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]
Accumulated postretirement benefit obligation - beginning of year	$ 12.0	$ 10.3
Service cost	0.7	0.7	0.7
Interest cost	0.6	0.6	0.5
Actuarial loss	0.5	1.4
Benefits paid	(0.3)	(0.2)
Curtailment	(0.4)	(0.8)
Accumulated postretirement benefit obligation - end of year	13.1	12.0	10.3
Assets at fair value - beginning of year	9.8	10.1
Return on plan assets	0.8	(0.1)
Benefits paid	(0.2)	(0.2)
Assets at fair value - end of year	10.4	9.8	10.1
Funded status	$ (2.7)	$ (2.2)