Leases (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 27, 2020	Mar. 29, 2019	Mar. 27, 2020	Mar. 29, 2019	Sep. 27, 2019
Leases [Abstract]
Document Period End Date			Mar. 27, 2020
Operating Leases, Future Minimum Payments Due, Next Twelve Months					$ 26.7
Operating Lease, Payments			$ 11.4
Operating Lease, Weighted Average Remaining Lease Term	8 years 6 months		8 years 6 months
Lessee, Operating Lease, Liability, Payments, Remainder of Fiscal Year	$ 9.9		$ 9.9
Operating Lease, Expense	6.3	$ 4.7	12.3	$ 9.4
Variable Lease, Cost	3.3		4.0
Lessee, Operating Lease, Liability, Payments, Due Year Two	23.7		23.7
Lessee, Operating Lease, Liability, Payments, Due Year Three	24.4		24.4
Lessee, Operating Lease, Liability, Payments, Due Year Four	23.8		23.8
Lessee, Operating Lease, Liability, Payments, Due Year Five	21.4		21.4
Lessee, Operating Lease, Liability, Payments, Due after Year Five	97.7		97.7
Lessee, Operating Lease, Liability, Payments, Due	200.9		200.9
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	(28.3)		(28.3)
Operating Lease, Liability	172.6		172.6
Operating Lease, Liability, Current	(20.7)		(20.7)
Operating Lease, Liability, Noncurrent	$ 151.9		$ 151.9		0.0
Operating Lease, Weighted Average Discount Rate, Percent	3.30%		3.30%
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability			$ 29.8
Operating Leases, Future Minimum Payments, Due in Two Years					25.9
Operating Leases, Future Minimum Payments, Due in Three Years					24.8
Operating Leases, Future Minimum Payments, Due in Four Years					23.3
Operating Leases, Future Minimum Payments, Due in Five Years					21.5
Operating Leases, Future Minimum Payments, Due Thereafter					97.7
Operating Leases, Future Minimum Payments Due					$ 219.9