Schedule of Reserve for Future Environmental Costs - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Sep. 28, 2012
Commitments and Contingencies [Line Items]
2013	$ 2.5
2014	1.2
2015	1.0
2016	0.9
2017	1.4
Thereafter	8.1
Total costs	15.1
Less imputed interest	(3.3)
Reserve amount	11.8
Recurring Costs
Commitments and Contingencies [Line Items]
2013	0.9
2014	0.7
2015	0.6
2016	0.7
2017	0.7
Thereafter	6.7
Total costs	10.3
Non Recurring Costs
Commitments and Contingencies [Line Items]
2013	1.6
2014	0.5
2015	0.4
2016	0.2
2017	0.7
Thereafter	1.4
Total costs	$ 4.8