Nature of Operations and Summary of Significant Accounting Policies (Narrative) (Details) $ in Thousands	1 Months Ended		12 Months Ended
	Apr. 30, 2020	Mar. 31, 2020	Oct. 02, 2022 USD ($) restaurant	Oct. 03, 2021 USD ($)	Sep. 27, 2020 USD ($)
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Restricted cash			$ 27,150	$ 18,222
Depreciation			55,800	46,500	$ 52,800
Deferred gift card income			18,525	17,892
Amounts recognized on unredeemed gift card balances			700	$ 600	$ 500
General liability and workers' comp estimated claims to be paid by insurance providers			$ 31,900
Contractual contributions	4.00%	2.00%	5.00%	5.00%	5.00%
Accrued advertising costs			$ 3,500	$ 9,500
Marketing and advertising expense			$ 32,600	19,600	$ 17,100
Entity Operated Units
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants | restaurant			146
Franchised Units
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants | restaurant			2,035
Sales Concentration Risk | Revenue Benchmark | Del Taco
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Concentration risk, percentage			4.00%
Other Assets
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Cash surrender value of life insurance			$ 108,900	123,600
Accrued Liabilities
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Deferred gift card income			$ 4,100	$ 2,200
Minimum
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment assigned lives			1 year
Maximum
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment assigned lives			35 years