Variable Interest Entities (Components Of FFE's Balance Sheet) (Details) (USD $) In Thousands, unless otherwise specified	Jan. 20, 2013		Sep. 30, 2012
Variable Interest Entity [Line Items]
Other current assets	$ 671		$ 375
Current liabilities	209,786		275,302
Other long-term liabilities	102,463		103,060
Retained earnings	1,141,360		1,120,671
Total liabilities and stockholders' equity	1,377,289		1,463,725
Jack In The Box Franchise Finance, LLC ("FFE") [Member]
Variable Interest Entity [Line Items]
Cash	0		444
Other current assets	2,286	[1]	2,536	[1]
Other assets, net	10,469	[1]	11,051	[1]
Total assets	12,755		14,031
Current liabilities	49		14
Other long-term liabilities	13,052	[2]	14,428	[2]
Retained earnings	(346)		(411)
Total liabilities and stockholders' equity	$ 12,755		$ 14,031

[1] Consists primarily of amounts due from franchisees.

[2] Consists primarily of the capital note contributions from Jack in the Box which are eliminated in consolidation.