Net Periodic Post-Retirement Benefit Expense (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Jan. 01, 2011	Jan. 02, 2010
Defined Benefit Plan Disclosure [Line Items]
Prior service credit amortization	$ 0.1
Other Postretirement Benefit Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Service cost	0.6	1.3	0.8
Interest cost	3.6	4.6	1.3
Prior service credit amortization	(1.2)	(0.2)	(0.2)
Actuarial loss amortization	(0.2)	(0.1)	(0.1)
Settlement / curtailment gain		(7.2)
Net periodic pension expense	$ 2.8	$ (1.6)	$ 1.8