Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 25, 2021	Jun. 26, 2020	Jun. 25, 2021	Jun. 26, 2020	Sep. 25, 2020
Income Tax Disclosure [Abstract]
Unrecognized tax benefits, gross	$ 67,500		$ 67,500		$ 60,700
Unrecognized tax benefits if recognized, would affect our effective tax rate	$ 45,600		$ 45,600		$ 42,000
Effective tax rate (as a percent)	7.70%	(68.50%)	12.20%	0.30%
Provision (benefit) for income taxes	$ (4,565)	$ 27,388	$ (37,859)	$ (580)
Federal tax rate	21.00%