Segment Reporting (Summarized Financial Information Of Reportable Segments) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended						4 Months Ended		12 Months Ended
	Sep. 28, 2014	Jul. 06, 2014	Apr. 13, 2014	Sep. 29, 2013	Jul. 07, 2013	Apr. 14, 2013	Jan. 19, 2014	Jan. 20, 2013	Sep. 28, 2014	Sep. 29, 2013	Sep. 30, 2012
Segment Reporting Information [Line Items]
Consolidated revenues	$ 344,687	$ 348,492	$ 340,870	$ 337,981	$ 350,329	$ 347,222	$ 450,081	$ 454,335	$ 1,484,131	$ 1,489,867	$ 1,509,295
Consolidated earnings from operations	29,225	43,000	32,879	36,699	30,884	27,447	57,204	43,175	162,308	138,205	120,816
Interest Income (Expense), Net									(15,678)	(15,251)	(18,874)
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest									146,630	122,954	101,942
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal									(3,548)	4,640	29,145
Expenditures for long-lived assets by segment									60,525	84,690	80,200
Consolidated depreciation expense									90,655	92,006	92,596
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									(3,548)
Jack in the box brand restaurant operations [Member]
Segment Reporting Information [Line Items]
Consolidated revenues									1,127,243
Consolidated earnings from operations									235,574
Expenditures for long-lived assets by segment									30,858
Consolidated depreciation expense									66,409
Jack In The Box [Member]
Segment Reporting Information [Line Items]
Consolidated revenues									1,127,243	1,179,295
Consolidated earnings from operations									130,408	113,864	96,302
Jack In The Box [Member]
Segment Reporting Information [Line Items]
Consolidated revenues											1,252,028
Expenditures for long-lived assets by segment									38,132	55,221	56,378
Consolidated depreciation expense									73,663	76,191	79,287
Qdoba brand restaurant operations [Member]
Segment Reporting Information [Line Items]
Consolidated revenues									356,888
Consolidated earnings from operations									34,287
Expenditures for long-lived assets by segment									17,967
Consolidated depreciation expense									16,992
Qdoba [Member]
Segment Reporting Information [Line Items]
Consolidated revenues									356,888	310,572	257,267
Consolidated earnings from operations									32,016	24,470	24,717
Expenditures for long-lived assets by segment									22,393	29,469	23,621
Consolidated depreciation expense										15,815	13,309
F F E Operations New [Member]
Segment Reporting Information [Line Items]
Consolidated earnings from operations									0
Discontinued Operation - Distribution Business [Member]
Segment Reporting Information [Line Items]
Expenditures for long-lived assets by segment									0	0	201
FFE Operations [Member]
Segment Reporting Information [Line Items]
Consolidated earnings from operations									(116)	(129)	(203)
Shared services and unallocated costs [Member]
Segment Reporting Information [Line Items]
Consolidated earnings from operations									(104,005)
Expenditures for long-lived assets by segment									11,700
Consolidated depreciation expense									7,254
Shared services and unallocated costs old reporting [Member]
Segment Reporting Information [Line Items]
Consolidated earnings from operations									0	0	0
Expenditures for long-lived assets by segment									0	0	0
Consolidated depreciation expense									0	0	0
Old segment reporting structure [Member]
Segment Reporting Information [Line Items]
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal									$ 0	$ 0	$ 0