Summary Of Refranchisings, Franchisee Development And Acquisitions (Number Of Restaurants Sold And Developed By Franchisees And Related Gains And Fees Recognized) (Details) (USD $)	12 Months Ended
	Sep. 28, 2014 restaurant		Sep. 29, 2013 restaurant		Sep. 30, 2012 restaurant
Summary Of Refranchisings, Franchisee Development And Acquisitions [Line Items]
Restaurants sold to franchisees (restaurants)	37		81		97
New restaurants opened by franchisees (restaurants)	33		45		50
Initial franchise fees received	$ 1,886,000		$ 4,017,000		$ 5,535,000
Proceeds from the sale of company-operated restaurants, Cash	10,536,000	[1]	30,619,000		47,115,000
Proceeds from the sale of company-operated restaurants, Notes receivable	0		0		1,200,000
Proceeds from the sale of company-operated restaurants	10,536,000		30,619,000		48,315,000
Net assets sold (primarily property and equipment)	(5,558,000)		(15,680,000)		(16,833,000)
Goodwill related to the sale of company-operated restaurants	(170,000)		(629,000)		(1,334,000)
Other	(6,500,000)	[2]	(9,670,000)	[2]	(1,003,000)
Gains on the sale of company-operated restaurants	(3,548,000)		4,640,000		29,145,000
Proceeds from extension of franchise and lease agreements	2,100,000		3,300,000		2,300,000
Jack In The Box [Member] | Loss on anticipated sale [Member]
Summary Of Refranchisings, Franchisee Development And Acquisitions [Line Items]
Gains on the sale of company-operated restaurants	(1,856,000)		0		0
Total gain (loss) on the sale of company-operated restaurants [Member]
Summary Of Refranchisings, Franchisee Development And Acquisitions [Line Items]
Gains on the sale of company-operated restaurants	(3,548,000)		4,640,000		29,145,000
Subtotal of gains (losses) on sale of company-operated restaurants [Member]
Summary Of Refranchisings, Franchisee Development And Acquisitions [Line Items]
Gains on the sale of company-operated restaurants	$ (1,692,000)		$ 4,640,000		$ 29,145,000

[1] Amounts in 2014, 2013 and 2012 include additional proceeds of $2.1 million, $3.3 million and $2.3 million, respectively, recognized upon the extension of the underlying franchise and lease agreements related to restaurants sold in a prior year.

[2] rimarily represent impairment and lease commitment charges related to restaurants closed in connection with the sale of the related markets