Contingencies and Legal Matters Contingencies and Legal Matters (Details) - USD ($) $ in Thousands				1 Months Ended			3 Months Ended	4 Months Ended
	Jan. 09, 2020	Jun. 11, 2019	Jan. 31, 2019	Nov. 30, 2019	Oct. 31, 2019	Feb. 28, 2019	Sep. 29, 2019	Jan. 19, 2020
Gessele v. Jack in the Box Inc.
Loss Contingencies [Line Items]
Alleged total potential damages			$ 62,000			$ 42,000
Claimed damages disallowed by the court				$ 25,000
Marquez v. Jack in the Box Inc.
Loss Contingencies [Line Items]
Net charge for estimated litigation liability								$ 3,800
Ramirez v. Jack in the Box Inc.
Loss Contingencies [Line Items]
Net charge for estimated litigation liability								7,300
Litigation insurance recovery receivable								$ 7,300
Ramirez v. Jack in the Box Inc. | Judicial Ruling
Loss Contingencies [Line Items]
Jury verdict for compensatory damages		$ 5,400
Jury verdict for punitive damages		$ 10,000
Plaintiff motion for attorney's fees, amount					$ 5,100
Attorney fees awarded	$ 3,900
Ramirez v. Jack in the Box Inc. | Judicial Ruling | Maximum
Loss Contingencies [Line Items]
Damages awarded							$ 15,400
Ramirez v. Jack in the Box Inc. | Judicial Ruling | Minimum
Loss Contingencies [Line Items]
Damages awarded							$ 3,200