Document And Entity Information	9 Months Ended
	Jul. 08, 2012	Aug. 03, 2012
Document And Entity Information [Abstract]
Entity Registrant Name	JACK IN THE BOX INC /NEW/
Entity Central Index Key	0000807882
Document Type	10-Q
Document Period End Date	Jul. 08, 2012
Amendment Flag	false
Current Fiscal Year End Date	--09-30
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	Q3
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		44,579,115