Summary of Refranchisings, Franchisee Development and Acquisitions (Purchase Price Allocations on Franchise Acquisitions) (Details) - restaurant	1 Months Ended	12 Months Ended
	Jan. 31, 2017	Sep. 29, 2019	Sep. 30, 2018	Oct. 01, 2017
Summary Of Refranchisings, Franchisee Development And Acquisitions [Line Items]
Number of restaurants acquired from franchisees		0	0	50
Number of restaurants closed				3
Number of restaurants sold to franchisees		0	135	178
2017 Reacquired Franchise Restaurants
Summary Of Refranchisings, Franchisee Development And Acquisitions [Line Items]
Number of restaurants closed				8
Number of restaurants sold to franchisees				42
Underperforming Franchisee
Summary Of Refranchisings, Franchisee Development And Acquisitions [Line Items]
Number of restaurants acquired from franchisees				31
Obtained Judgment
Summary Of Refranchisings, Franchisee Development And Acquisitions [Line Items]
Number of restaurants acquired from franchisees	19