Revenue (Disaggregation of Revenue) (Details) - USD ($) $ in Thousands	12 Months Ended
	Oct. 01, 2023	Oct. 02, 2022	Oct. 03, 2021	Sep. 27, 2020
Disaggregation of Revenue [Line Items]
Revenues	$ 1,692,306	$ 1,468,083	$ 1,143,670
Jack in the Box
Disaggregation of Revenue [Line Items]
Revenues	1,195,311	1,151,188	1,143,670	$ 1,143,670
Del Taco
Disaggregation of Revenue [Line Items]
Revenues	496,995	316,895	0
Company restaurant sales
Disaggregation of Revenue [Line Items]
Revenues	846,278	701,070	387,766
Company restaurant sales | Jack in the Box
Disaggregation of Revenue [Line Items]
Revenues	413,748	414,225	387,766
Company restaurant sales | Del Taco
Disaggregation of Revenue [Line Items]
Revenues	432,530	286,845	0
Franchise contracts
Disaggregation of Revenue [Line Items]
Revenues	364,591	340,391	346,634
Franchise contracts | Jack in the Box
Disaggregation of Revenue [Line Items]
Revenues	351,283	335,936	346,634
Franchise contracts | Del Taco
Disaggregation of Revenue [Line Items]
Revenues	13,308	4,455	0
Franchise royalties
Disaggregation of Revenue [Line Items]
Revenues	232,733	202,316	193,908
Franchise royalties | Jack in the Box
Disaggregation of Revenue [Line Items]
Revenues	207,064	188,902	193,908
Franchise royalties | Del Taco
Disaggregation of Revenue [Line Items]
Revenues	25,669	13,414	0
Franchise advertising contributions
Disaggregation of Revenue [Line Items]
Revenues	220,942	193,983	188,184
Franchise advertising contributions | Jack in the Box
Disaggregation of Revenue [Line Items]
Revenues	199,917	183,076	188,184
Franchise advertising contributions | Del Taco
Disaggregation of Revenue [Line Items]
Revenues	21,025	10,907	0
Technology and sourcing fees
Disaggregation of Revenue [Line Items]
Revenues	19,980	15,818	16,361
Technology and sourcing fees | Jack in the Box
Disaggregation of Revenue [Line Items]
Revenues	16,073	14,740	16,361
Technology and sourcing fees | Del Taco
Disaggregation of Revenue [Line Items]
Revenues	3,907	1,078	0
Franchise fees and other services
Disaggregation of Revenue [Line Items]
Revenues	7,782	14,505	10,817
Franchise fees and other services | Jack in the Box
Disaggregation of Revenue [Line Items]
Revenues	7,226	14,309	10,817
Franchise fees and other services | Del Taco
Disaggregation of Revenue [Line Items]
Revenues	$ 556	$ 196	$ 0