Nature Of Operations And Summary Of Significant Accounting Policies (Summary Of Number Of Restaurants) (Details)	Sep. 28, 2014 restaurant	Sep. 29, 2013 restaurant	Sep. 30, 2012 restaurant
Jack In The Box [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants	2,250	2,251	2,250
Qdoba [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants	638	615	627
Company-Operated [Member] | Jack In The Box [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants	431	465	547
Company-Operated [Member] | Qdoba [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants	310	296	316
Franchise [Member] | Jack In The Box [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants	1,819	1,786	1,703
Franchise [Member] | Qdoba [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants	328	319	311