Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 28, 2018	Sep. 29, 2017	Sep. 30, 2016
Commitments And Contingencies [Line Items]
Minimum rentals under operating leases fiscal year 2019	$ 25.9
Minimum rentals under operating leases fiscal year 2020	22.4
Minimum rentals under operating leases fiscal year 2021	19.3
Minimum rentals under operating leases fiscal year 2022	15.4
Minimum rentals under operating leases fiscal year 2023	11.8
Minimum rentals, thereafter	17.8
Rental expenses	28.7	$ 26.4	$ 24.3
Purchase obligation, due in fiscal year 2019	41.2
Purchase obligation, due in fiscal year 2020	28.2
Purchase obligation, due in fiscal year 2021	6.4
Purchase obligation, due in fiscal year 2022	5.2
Purchase obligation, due in fiscal year 2023	3.2
Purchase obligation, thereafter	4.3
Environmental cleanup costs, third-party claim costs, project management costs and legal costs	0.8	0.7	$ 0.9
Receivables of past and future environmental-related expenditures	1.4	$ 1.6
Restructuring Charges (Reversals)	0.0
Cercla Sites And One Past Facility
Commitments And Contingencies [Line Items]
Amount accrued for environmental remediation expense	0.9
Cercla Sites And One Past Facility | Minimum
Commitments And Contingencies [Line Items]
Estimated environmental remediation costs	$ 0.9
Estimated time frames to resolve contingency related to environmental remediation contingencies (in years)	1 year
Cercla Sites And One Past Facility | Maximum
Commitments And Contingencies [Line Items]
Estimated environmental remediation costs	$ 5.2
Estimated time frames to resolve contingency related to environmental remediation contingencies (in years)	30 years
Other Sites
Commitments And Contingencies [Line Items]
Amount accrued for environmental remediation expense	$ 4.5
Site contingency loss best estimate	5.1
Accrual for environmental loss contingencies discount rate (as a percent)		4.00%
Other Sites | Minimum
Commitments And Contingencies [Line Items]
Estimated environmental remediation costs	$ 3.8
Estimated time frames to resolve contingency related to environmental remediation contingencies (in years)	1 year
Other Sites | Maximum
Commitments And Contingencies [Line Items]
Estimated environmental remediation costs	$ 17.9
Estimated time frames to resolve contingency related to environmental remediation contingencies (in years)	30 years
2017 Restructuring Plan
Commitments And Contingencies [Line Items]
Restructuring Charges (Reversals)	$ 0.0	$ 13.2
Other Long-term Liabilities
Commitments And Contingencies [Line Items]
Long-term warranty accrual	$ 3.9	$ 4.3