Commitments and Contingencies - Additional Information (Detail) $ in Millions	12 Months Ended
	Sep. 28, 2019 USD ($) Lease term	Sep. 29, 2018 USD ($)	Sep. 30, 2017 USD ($)
Contingent Consideration Earn-Out Payments [Line Items]
Accrued expenses	$ 430.9	$ 436.1
Rent expense net of sublease income	23.1	23.1	$ 19.3
Rent expense on sublease rentals	$ 2.7	$ 2.6	$ 2.3
Finance Leases [Member]
Contingent Consideration Earn-Out Payments [Line Items]
Number of finance leases | Lease	2
Fair value	$ 28.3
Accrued expenses	1.6
Accrued lease obligation-long-term	$ 33.6
Optional lease extension period	10 years
Number of optional lease extensions | term	2
Lease extension period	5 years
Finance Lease 2 [Member]
Contingent Consideration Earn-Out Payments [Line Items]
Optional lease extension period	6 years
Number of optional lease extensions | term	1
Lease extension period	5 years
Finance Leases [Member] | Leasehold Improvements [Member]
Contingent Consideration Earn-Out Payments [Line Items]
Property, plant and equipment, estimated useful life	35 years