Basis Of Presentation (Details)	Jan. 20, 2013 restaurant	Jan. 22, 2012 restaurant
Jack In The Box [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants	2,255	2,236
Qdoba [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants	636	597
Company Operated [Member] | Jack In The Box [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants	551	634
Company Operated [Member] | Qdoba [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants	325	262
Franchised [Member] | Jack In The Box [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants	1,704	1,602
Franchised [Member] | Qdoba [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants	311	335