SCHEDULE II VALUATION AND QUALIFYING ACCOUNTS (Details) - USD ($) $ in Thousands		12 Months Ended
		Sep. 26, 2020	Sep. 28, 2019	Sep. 29, 2018
Allowance for Doubtful Accounts [Member]
Valuation And Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period		$ 2,573	$ 3,629	$ 3,044
Charged (credited) to Costs and Expenses		3,855	2,580	4,443
Other Additions		0	0	0
Deductions	[1]	(1,955)	(3,636)	(3,858)
Balance at End of Period		4,473	2,573	3,629
Valuation Allowance of Deferred Tax Assets [Member]
Valuation And Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period		37,996	37,881	59,188
Charged (credited) to Costs and Expenses		(298)	115	(1,366)
Other Additions		0	0	0
Deductions	[1]	0	0	(19,941)
Balance at End of Period		$ 37,698	$ 37,996	$ 37,881

[1] Represents amounts that did not impact earnings.