Impairment, Disposition Of Property And Equipment, And Restaurant Closing Costs (Restaurant Closing Costs) (Details) - USD ($)		12 Months Ended
		Oct. 01, 2017		Oct. 02, 2016	Sep. 27, 2015
Restructuring Reserve [Roll Forward]
Asset Impairment Charges		$ 3,096,000		$ 544,000	$ 557,000
Facility Closing [Member]
Restructuring Reserve [Roll Forward]
Balance at beginning of year		7,231,000
Additions and adjustments		549,000
Restructuring Reserve, Accrual Adjustment	[1]	959,000
Cash payments		4,130,000
Balance at end of year		6,203,000	[2],[3]	$ 7,231,000
Restaurant Closing Costs [Member]
Restructuring Reserve [Roll Forward]
Other Accrued Liabilities		$ 2,900,000
Weighted Average [Member] | Facility Closing [Member]
Restructuring Cost and Reserve [Line Items]
RemainingLeaseCommitmentTerm		4
Interest Expense [Member] | Facility Closing [Member]
Restructuring Reserve [Roll Forward]
Restructuring Reserve, Accrual Adjustment		$ 1,594,000
Qdoba brand restaurant operations [Member]
Restructuring Reserve [Roll Forward]
Asset Impairment Charges		$ 700,000.0

[1] (1)Adjustments relate primarily to revisions of certain sublease and cost assumptions. Our estimates related to our future lease obligations, primarily the sublease income we anticipate, are subject to a high degree of judgment and may differ from actual sublease income due to changes in economic conditions, desirability of the sites and other factors.

[2] (3)This balance excludes $2.9 million of restaurant closing costs that are included in accrued liabilities and other long-term liabilities, which were initially recorded as losses on the sale of company-operated restaurants upon sale to Jack in the Box franchisees in prior years.

[3] The weighted average remaining lease term related to these commitments is approximately four years