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Nature Of Operations And Summary Of Significant Accounting Policies (Summary Of Advertising Costs) (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2018	Oct. 01, 2017	Oct. 02, 2016
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Marketing and Advertising Expense	$ 28.8	$ 36.5	$ 41.2
Current Fiscal Year End Date	--09-30
Document Fiscal Year Focus	2018
ContractualContributionsTowardsAdvertisingCostsPercentageOfSales	5.00%
Marketing Expense	$ 6.2	$ 0.5	$ 1.1
Jack in the box brand restaurant operations [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
ContractualContributionsTowardsAdvertisingCostsPercentageOfSales			5.00%
Qdoba brand restaurant operations [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
ContractualContributionsTowardsAdvertisingCostsPercentageOfSales			2.00%

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This is focus fiscal year of the document report in CCYY format. For a 2006 annual report, which may also provide financial information from prior periods, fiscal 2006 should be given as the fiscal year focus. Example: 2006.

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The total expense recognized in the period for promotion, public relations, and brand or product advertising.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
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Expenditures for planning and executing the conception, pricing, promotion, and distribution of ideas, goods, and services. Costs of public relations and corporate promotions are typically considered to be marketing costs.

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