Nature Of Operations And Summary Of Significant Accounting Policies (Narrative) (Details) (USD $)	12 Months Ended
	Sep. 30, 2012 Y	Oct. 02, 2011	Oct. 03, 2010
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Fiscal year	P52W	P52W	P53W
Depreciation and amortization expense	$ 96,487,000	$ 94,845,000	$ 100,285,000
Goodwill and intangible asset impairment	0
Cash surrender value of policy	85,500,000	73,300,000
Cash included in trust	700,000	1,900,000
Book overdrafts	40,500,000	32,000,000
Period of franchise agreement (in years)	20
Revenue recognized on unredeemed gift cards	500,000	600,000	700,000
Jack In The Box [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Depreciation and amortization expense	79,287,000	81,827,000	90,168,000
Marketing funds including contractual contributions	5.00%	5.00%	5.00%
Qdoba [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Depreciation and amortization expense	$ 17,200,000	$ 13,018,000	$ 10,117,000
Marketing funds including contractual contributions	1.00%	1.00%	1.00%
Equipment Asset [Member] | Equipment Asset [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment assigned lives, minimum (in years)	2
Property, plant and equipment assigned lives, maximum (in years)	35
Building And Leasehold Improvement [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment assigned lives, minimum (in years)	2
Property, plant and equipment assigned lives, maximum (in years)	35