Goodwill And Intangible Assets, Net (Changes In Carrying Amount Of Goodwill) (Details) - USD ($) $ in Thousands	12 Months Ended
Oct. 01, 2017	Oct. 02, 2016	Sep. 27, 2015
Goodwill [Roll Forward]
Goodwill, beginning balance	$ 166,046	$ 149,027
Acquisition of franchised restaurants	13,059	17,034
Sale of company-operated restaurants to franchisees	(10,056)	(15)
Goodwill, ending balance	169,049	166,046	$ 149,027
Jack in the box brand restaurant operations [Member]
Goodwill [Roll Forward]
Goodwill, beginning balance	48,415	48,430
Acquisition of franchised restaurants	13,059	0	0
Sale of company-operated restaurants to franchisees	(10,056)	(15)	(47)
Goodwill, ending balance	51,418	48,415	48,430
Qdoba brand restaurant operations [Member]
Goodwill [Roll Forward]
Goodwill, beginning balance	117,631	100,597
Acquisition of franchised restaurants	0	17,034
Sale of company-operated restaurants to franchisees	0	0
Goodwill, ending balance	$ 117,631	$ 117,631	$ 100,597

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.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=64834752&loc=SL49117168-202975

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Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

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Amount of divestiture 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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