Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 26, 2020	Jun. 28, 2019	Jun. 26, 2020	Jun. 28, 2019	Sep. 27, 2019
Income Tax Disclosure [Abstract]
Unrecognized tax benefits, gross	$ 60,900		$ 60,900		$ 108,500
Unrecognized tax benefits if recognized, would affect our effective tax rate	$ 36,600		$ 36,600		$ 72,800
Effective tax rate (as a percent)	(68.50%)	5.20%	0.30%	6.40%
Provision (benefit) for income taxes	$ (27,388)	$ 2,163	$ 580	$ 14,486
Federal tax rate	21.00%