Document And Entity Information - shares	4 Months Ended
	Jan. 17, 2016	Feb. 12, 2016
Entity Information [Line Items]
Entity Registrant Name	JACK IN THE BOX INC /NEW/
Entity Central Index Key	0000807882
Current Fiscal Year End Date	--10-02
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Jan. 17, 2016
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding		34,681,826