Impairment and Other Charges, Net (Restructuring Costs) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 27, 2020	Sep. 29, 2019	Sep. 30, 2018
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 1,168	$ 8,455	$ 10,647
Employee severance and related costs
Restructuring Cost and Reserve [Line Items]
Restructuring costs	1,168	7,169	7,845
Strategic Alternatives Evaluation
Restructuring Cost and Reserve [Line Items]
Restructuring costs	0	1,286	0
Qdoba Evaluation
Restructuring Cost and Reserve [Line Items]
Restructuring costs	0	0	2,211
Other
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 0	$ 0	$ 591