Components of Net Periodic Benefit Cost (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Sep. 28, 2012
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	$ (0.1)
Net loss	(2.8)
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year, Total	(2.9)
Defined Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	(0.1)
Net loss	(2.7)
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year, Total	(2.8)
Post-Retirement Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	0
Net loss	(0.1)
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year, Total	$ (0.1)