Fair Value of Plan Assets (Detail) (USD $) In Millions, unless otherwise specified	Dec. 28, 2012	Dec. 30, 2011	Dec. 31, 2010
Defined Benefit Plan Disclosure [Line Items]
Total assets	$ 10.4	$ 9.8	$ 10.1
Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Total assets	4.2	3.6
Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Total assets	6.2	2.6
Guaranteed Income Fund
Defined Benefit Plan Disclosure [Line Items]
Total assets		3.6
Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Total assets	10.4	6.2
Quoted Prices in Active Markets for Identical Assets (Level 1) | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Total assets	4.2	3.6
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Total assets	6.2	2.6
Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Total assets		3.6
Significant Other Observable Inputs (Level 2) | Guaranteed Income Fund
Defined Benefit Plan Disclosure [Line Items]
Total assets		$ 3.6