Variable Interest Entities (Components Of FFE's Balance Sheet) (Details) (USD $) In Thousands, unless otherwise specified	Apr. 12, 2015		Sep. 28, 2014
Variable Interest Entity [Line Items]
Other current assets	$ 2,097		$ 597
Current liabilities	199,036		206,307
Other long-term liabilities	307,433		309,435
Retained earnings	1,288,272		1,244,897
Total liabilities and stockholders' equity	1,262,403		1,270,665
Jack In The Box Franchise Finance, LLC (FFE) [Member]
Variable Interest Entity [Line Items]
Cash	0		0
Other current assets	1,072	[1]	2,494	[1]
Other assets, net	2,539	[1]	5,776	[1]
Total assets	3,611		8,270
Current liabilities	1,203	[2]	2,833	[2]
Other long-term liabilities	2,276	[2]	5,367	[2]
Retained earnings	132		70
Total liabilities and stockholders' equity	$ 3,611		$ 8,270

[1] Consists primarily of amounts due from franchisees.

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