Segment Reporting (Summarized Financial Information Of Reportable Segments) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
Apr. 12, 2015	Apr. 13, 2014	Apr. 12, 2015	Apr. 13, 2014	Sep. 28, 2014
Segment Reporting Information [Line Items]
Consolidated revenues	$ 358,122us-gaap_Revenues	$ 340,870us-gaap_Revenues	$ 826,743us-gaap_Revenues	$ 790,952us-gaap_Revenues
Consolidated earnings from operations	41,868us-gaap_OperatingIncomeLoss	32,879us-gaap_OperatingIncomeLoss	105,104us-gaap_OperatingIncomeLoss	90,083us-gaap_OperatingIncomeLoss
Interest Income (Expense), Net	4,220us-gaap_InterestIncomeExpenseNet	4,311us-gaap_InterestIncomeExpenseNet	9,433us-gaap_InterestIncomeExpenseNet	8,853us-gaap_InterestIncomeExpenseNet
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	37,648	28,568	95,671	81,230
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal	(5,020)	1,757	(4,170)	2,218
Consolidated depreciation expense	20,346us-gaap_Depreciation	21,109us-gaap_Depreciation	47,501us-gaap_Depreciation	49,329us-gaap_Depreciation
Consolidated goodwill	149,042us-gaap_Goodwill		149,042us-gaap_Goodwill		149,074us-gaap_Goodwill
Goodwill, Written off Related to Sale of Business Unit	(16)	(120)	(32)	(129)
Qdoba brand restaurant operations [Member]
Segment Reporting Information [Line Items]
Consolidated revenues	88,678	80,781	205,348	181,040
Consolidated earnings from operations	8,778	7,105	23,460	16,713
Consolidated depreciation expense	4,035	3,906	9,315	9,136
Consolidated goodwill	100,597		100,597		100,597
Goodwill, Written off Related to Sale of Business Unit			0
Jack in the box brand restaurant operations [Member]
Segment Reporting Information [Line Items]
Consolidated revenues	269,444	260,089	621,395	609,912
Consolidated earnings from operations	64,313	53,617	145,168	129,920
Consolidated depreciation expense	14,699	15,418	34,314	36,269
Consolidated goodwill	48,445		48,445		48,477
Goodwill, Written off Related to Sale of Business Unit			(32)
Shared services and unallocated costs [Member]
Segment Reporting Information [Line Items]
Consolidated earnings from operations	(26,203)	(29,600)	(59,354)	(58,768)
Consolidated depreciation expense	1,612	1,785	3,872	3,924
Total gain (loss) on the sale of company-operated restaurants [Member]
Segment Reporting Information [Line Items]
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal	(5,020)	1,757	(4,170)	2,218
Subtotal of gains (losses) on sale of company-operated restaurants [Member]
Segment Reporting Information [Line Items]
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal	$ (5,020)	$ 4,872		$ 5,333

The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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This element represents the income or loss from continuing operations attributable to the economic entity which may also be defined as revenue less expenses from ongoing operations, after income or loss from equity method investments, but before income taxes, extraordinary items, and noncontrolling interest.

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The net amount of operating interest income (expense).

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