Nature of Operations and Summary of Significant Accounting Policies (Narrative) (Details) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended	12 Months Ended
	Apr. 30, 2020	Mar. 31, 2020	Dec. 31, 2020	Oct. 03, 2021	Sep. 27, 2020	Sep. 29, 2019
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Number of weeks per fiscal year				53	52	52
Restricted cash				$ 18,222	$ 37,258
Depreciation				46,500	52,800	$ 55,200
Intangible assets, carrying value				470	277
Amounts recognized on unredeemed gift card balances				600	500	500
General liability and workers' comp estimated claims to be paid by insurance providers				$ 1,800	1,900
Contractual contributions		4.00%		5.00%
Collection period for marketing fees		24 months	3 months
Uncollected postponed marketing fees				$ 4,300
Accrued advertising costs				9,500	8,300
Incremental corporate advertising contributions				0		2,000
Marketing and advertising expense				19,600	17,100	$ 19,000
Other Assets
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Cash surrender value of life insurance				$ 123,600	$ 113,800
Minimum
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment assigned lives				1 year
Contractual contributions	2.00%
Maximum
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment assigned lives				35 years
Contractual contributions	4.00%