Document And Entity Information - shares
4 Months Ended
Jan. 22, 2017
Feb. 17, 2017
Entity Information [Line Items]    
Entity Common Stock, Shares Outstanding   31,641,734
Entity Registrant Name JACK IN THE BOX INC /NEW/  
Entity Central Index Key 0000807882  
Current Fiscal Year End Date --10-01  
Entity Filer Category Large Accelerated Filer  
Document Type 10-Q  
Document Period End Date Jan. 22, 2017  
Document Fiscal Year Focus 2017  
Document Fiscal Period Focus Q1  
Amendment Flag false