Leases - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2021	Mar. 28, 2020	Mar. 31, 2021	Mar. 28, 2020	Sep. 30, 2020	Feb. 28, 2019
Lessee Lease Description [Line Items]
Payments to be received as sublease income						$ 9,100
Operating right-of-use lease assets	$ 148,684		$ 148,684		$ 149,933
Operating lease, liability	206,384		206,384
Lease Cost
Operating cash flows from operating leases	14,016	$ 9,642	28,076	$ 15,140
Facility Closures and Related Costs
Lessee Lease Description [Line Items]
Operating lease liability, net restructured facilities	5,300		5,300		$ 11,300
Operating right-of-use lease assets	1,900		1,900
Operating lease, liability	7,200		7,200
Lease Cost
Operating cash flows from operating leases	2,500	$ 2,100	6,300	$ 4,500
Facility Closures and Related Costs | Operating Lease Short Term Lease Obligation
Lessee Lease Description [Line Items]
Operating lease, liability	4,700		4,700
Facility Closures and Related Costs | Operating Lease Long Term Lease Obligation
Lessee Lease Description [Line Items]
Operating lease, liability	2,500		2,500
Sublease Income Committed
Lessee Lease Description [Line Items]
Sublease income assumed	$ 1,900		$ 1,900