Impairment, Disposition Of Property And Equipment, And Restaurant Closing Costs (Impairment And Disposal Costs Included In Impairment And Other Charges) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Apr. 15, 2012	Apr. 17, 2011	Apr. 15, 2012	Apr. 17, 2011
Impairment, Disposition Of Property And Equipment, And Restaurant Closing Costs [Abstract]
Impairment charges	$ 910	$ 878	$ 2,109	$ 1,167
Losses on the disposition of property and equipment, net	$ 1,775	$ 2,628	$ 2,858	$ 5,424
Number of underperforming Jack in the Box restaurants subject to impairment charges			3
Number of Jack in the Box restaurants closed or intended to close subject to impairment charges			3