Schedule of Liabilities for Future Environmental Costs (Detail) (USD $) In Millions, unless otherwise specified	Sep. 26, 2014
Commitments And Contingencies [Line Items]
2015	$ 2.3
2016	1.1
2017	1.0
2018	0.8
2019	1.3
Thereafter	6.6
Total costs	13.1
Less imputed interest	3.3
Reserve amount	9.8
Recurring Costs
Commitments And Contingencies [Line Items]
2015	0.7
2016	0.6
2017	0.5
2018	0.6
2019	0.7
Thereafter	5.2
Total costs	8.3
Non-Recurring Costs
Commitments And Contingencies [Line Items]
2015	1.6
2016	0.5
2017	0.5
2018	0.2
2019	0.6
Thereafter	1.4
Total costs	$ 4.8