Basis Of Presentation (Details) $ in Thousands	6 Months Ended
	Apr. 16, 2017 USD ($) restaurant	Apr. 10, 2016 USD ($) restaurant	Oct. 02, 2016 USD ($)
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation | $	$ 4,000
Defined Benefit Plan, Net Periodic Benefit Cost Excluding Service Cost | $	$ 1,100	$ 4,400
Jack in the box brand restaurant operations [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants	2,260	2,251
Jack in the box brand restaurant operations [Member] | Entity Operated Units [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants	371	413
Jack in the box brand restaurant operations [Member] | Franchised Units [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants	1,889	1,838
Qdoba brand restaurant operations [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants	717	683
Qdoba brand restaurant operations [Member] | Entity Operated Units [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants	377	338
Qdoba brand restaurant operations [Member] | Franchised Units [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants	340	345
Current Maturities of Long-Term Debt [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Unamortized Debt Issuance Expense | $			$ 1,600
Long-Term Debt, Net of Current Maturities [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Unamortized Debt Issuance Expense | $			2,200
Term Loan [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Unamortized Debt Issuance Expense | $			$ 3,800