Significant Accounting Policies - Accounts receivable Allowances (Details) - USD ($) $ in Thousands	12 Months Ended
	Oct. 03, 2020	Sep. 28, 2019	Sep. 29, 2018
Accounts Receivable, Allowance for Doubtful Accounts [Roll Forward]
Beginning balance	$ 8,690	$ 4,568	$ 6,890
Additions charged to expenses	2,630	5,210	1,980
Accruals related to acquisitions	0	0	37
Deductions from reserves	(3,690)	(1,088)	(4,339)
Ending balance	$ 7,630	$ 8,690	$ 4,568