Income Taxes Expense (Benefit) - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 29, 2012	Oct. 01, 2011	Sep. 29, 2012	Oct. 01, 2011
Income Tax Expenses [Line Items]
Income tax expense	$ 1.2	$ (4.0)	$ 5.5	$ (1.7)
Pretax income			54.4	50.9
Deferred tax allowances			4.3
Adjustment in income tax expense			$ 1.8