Nature Of Operations And Summary Of Significant Accounting Policies (Summary Of Advertising Costs) (Details) - USD ($) $ in Thousands	12 Months Ended
	Oct. 01, 2017	Oct. 02, 2016	Sep. 27, 2015
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Marketing and Advertising Expense	$ 58,210	$ 61,677	$ 59,582
Jack in the box brand restaurant operations [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Contractual Contributions Towards Advertising Costs Percentage Of Sales	5.00%	5.00%	5.00%
Marketing and Advertising Expense	$ 36,489	$ 41,189	$ 41,895
Qdoba brand restaurant operations [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Contractual Contributions Towards Advertising Costs Percentage Of Sales	1.30%	2.00%	2.00%
Marketing and Advertising Expense	$ 21,721	$ 20,488	$ 17,687