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Segment Reporting (Summarized Financial Information Of Reportable Segments) (Details) - USD ($) $ in Thousands	3 Months Ended						4 Months Ended		12 Months Ended
	Oct. 02, 2016	Jul. 03, 2016	Apr. 10, 2016	Sep. 27, 2015	Jul. 05, 2015	Apr. 12, 2015	Jan. 17, 2016	Jan. 18, 2015	Oct. 02, 2016	Sep. 27, 2015	Sep. 28, 2014
Segment Reporting Information [Line Items]
Consolidated revenues	$ 398,419	$ 368,938	$ 361,151	$ 354,068	$ 359,506	$ 358,122	$ 470,823	$ 468,621	$ 1,599,331	$ 1,540,317	$ 1,484,131
Consolidated earnings from operations	$ 58,910	$ 55,705	$ 52,786	$ 41,674	$ 50,395	$ 41,868	$ 62,514	$ 63,236	229,915	197,173	162,308
Gains (losses) on the sale of company-operated restaurants									1,230	(3,139)	(3,548)
Interest expense, net									31,081	18,803	15,678
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest									198,834	178,370	146,630
Expenditures for long-lived assets by segment									96,615	86,226	60,525
Consolidated depreciation expense									92,082	88,778	90,655
Operating Segments [Member] \| Jack in the box brand restaurant operations [Member]
Segment Reporting Information [Line Items]
Consolidated revenues									1,162,258	1,145,176	1,127,243
Consolidated earnings from operations									290,346	265,230	235,574
Expenditures for long-lived assets by segment									38,607	41,928	30,858
Consolidated depreciation expense									66,287	64,597	66,409
Operating Segments [Member] \| Qdoba brand restaurant operations [Member]
Segment Reporting Information [Line Items]
Consolidated revenues									437,073	395,141	356,888
Consolidated earnings from operations									47,250	47,264	34,287
Expenditures for long-lived assets by segment									53,316	34,071	17,967
Consolidated depreciation expense									19,306	17,103	16,992
Corporate, Non-Segment [Member] \| Shared services and unallocated costs [Member]
Segment Reporting Information [Line Items]
Consolidated earnings from operations									(108,911)	(112,182)	(104,005)
Expenditures for long-lived assets by segment									4,692	10,227	11,700
Consolidated depreciation expense									6,489	7,078	7,254
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Gains (losses) on the sale of company-operated restaurants									$ 1,230	$ (3,139)	$ (3,548)