Leases - Supplemental Balance Sheet Information (Details) - USD ($)	Jun. 27, 2020	Sep. 28, 2019
Lessee, Lease, Description [Line Items]
Finance lease liabilities (current)		$ 1,800,000
Finance lease liabilities (non-current)		$ 19,200,000
Operating Lease, Weighted Average Remaining Lease Term	5 years 8 months 15 days
Finance Lease, Weighted Average Remaining Lease Term	7 years 10 months 20 days
Operating Leases, Weighted average discount rate	2.00%
Financing Leases, Weighted average discount rate	5.10%
Other assets
Lessee, Lease, Description [Line Items]
Operating Leases, Lease right-of-use asset	$ 83,000.0
Accrued expenses
Lessee, Lease, Description [Line Items]
Operating lease liabilities (current)	22,900
Finance lease obligations - short term
Lessee, Lease, Description [Line Items]
Finance lease liabilities (current)	1,800
Other long-term liabilities
Lessee, Lease, Description [Line Items]
Operating lease liabilities (non-current)	68,300
Finance lease obligations - long term
Lessee, Lease, Description [Line Items]
Finance lease liabilities (non-current)	$ 17,900