Restructuring and Other Charges - Additional Information (Details) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Mar. 31, 2021 USD ($)	Mar. 28, 2020 USD ($)	Mar. 31, 2021 USD ($)	Mar. 28, 2020 USD ($)	Sep. 30, 2020 USD ($) Employee	Sep. 30, 2019 USD ($)
Restructuring Cost And Reserve [Line Items]
Restructuring and other charges, net	$ (469)	$ (18,242)	$ (716)	$ (32,276)
Restructuring charges	(200)	(13,200)	(362)	(26,996)
Restructuring Reserve	4,973	24,668	4,973	24,668	$ 9,987	$ 31,086
Impairment and Accretion Expense Related to Exited Facilities
Restructuring Cost And Reserve [Line Items]
Restructuring and other charges, net	(300)	(4,700)	(300)	(5,000)
Accelerated Depreciation Planned Facility Exit
Restructuring Cost And Reserve [Line Items]
Restructuring and other charges, net		(300)		(300)
Employee Severance and Related Benefits
Restructuring Cost And Reserve [Line Items]
Restructuring charges			(163)	(31,358)
Restructuring Reserve	262	17,485	262	17,485	3,992	298
Employee Severance and Related Benefits | Restructuring Plan 2020
Restructuring Cost And Reserve [Line Items]
Restructuring charges			(200)		$ (30,800)
Number of employees | Employee					250
Facility Closures and Related Costs
Restructuring Cost And Reserve [Line Items]
Restructuring charges			(199)	4,362
Restructuring Reserve	4,711	$ 7,183	4,711	$ 7,183	$ 5,995	$ 30,788
Facility Closures and Related Costs | Accrued Expenses and Other Current Liabilities
Restructuring Cost And Reserve [Line Items]
Restructuring Reserve	2,600		2,600
Facility Closures and Related Costs | Other Noncurrent Liabilities
Restructuring Cost And Reserve [Line Items]
Restructuring Reserve	$ 2,100		$ 2,100