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Impairment and Other Charges, Net - Accrued severance (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jul. 05, 2020	Jul. 07, 2019	Jul. 05, 2020	Jul. 07, 2019
Restructuring Reserve [Roll Forward]
Costs incurred	$ 2	$ (64)	$ 1,165	$ 6,722
Employee Severance and Related Costs
Restructuring Reserve [Roll Forward]
Balance as of September 29, 2019			2,100
Costs incurred	2	$ 287	1,165	$ 5,436
Cash payments			(3,265)
Balance as of July 5, 2020	$ 0		0
Employee Severance & Other
Restructuring Reserve [Roll Forward]
Costs incurred			$ 1,165