Goodwill And Intangible Assets, Net (Changes In Carrying Amount Of Goodwill) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Sep. 30, 2012	Oct. 02, 2011	Oct. 03, 2010
Goodwill [Roll Forward]
Goodwill, beginning balance	$ 105,872	$ 85,041
Acquisition of franchised restaurants	36,084	24,300	1,058
Sale of company-operated restaurants to franchisees	(1,334)	(3,469)	(1,860)
Goodwill, ending balance	140,622	105,872	85,041
Jack In The Box [Member]
Goodwill [Roll Forward]
Goodwill, beginning balance	49,181	52,650
Acquisition of franchised restaurants	0	0
Sale of company-operated restaurants to franchisees	(1,334)	(3,469)
Goodwill, ending balance	47,847	49,181
Qdoba [Member]
Goodwill [Roll Forward]
Goodwill, beginning balance	56,691	32,391
Acquisition of franchised restaurants	36,084	24,300
Sale of company-operated restaurants to franchisees	0	0
Goodwill, ending balance	$ 92,775	$ 56,691

Carrying amount as of the balance sheet date, which is the cumulative amount paid and (if applicable) the fair value of any noncontrolling interest in the acquiree, adjusted for any amortization recognized prior to the adoption of any changes in generally accepted accounting principles (as applicable) and for any impairment charges, in excess of the fair value of net assets acquired in one or more business combination transactions.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 142

-Paragraph 45

-Subparagraph e

-Clause 1

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 142

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141R

-Paragraph 68

-Subparagraph l

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 142

-Paragraph 45

-Subparagraph e

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141R

-Paragraph 34

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Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141R

-Paragraph 72

-Subparagraph d

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+ Details

- Definition

The aggregate amount of goodwill acquired in the period and allocated to the reportable segment. The value is stated at fair value based on the purchase price allocation.

+ References+ Details

- Definition

Write-off of the carrying amount of goodwill associated with all or a portion of a reporting unit that is sold in the period.

+ References+ Details