COMMITMENTS AND CONTINGENCIES - Additional Information (Details)			3 Months Ended	12 Months Ended
	May 21, 2021 USD ($)	Mar. 17, 2017	Sep. 23, 2020 USD ($)	Dec. 28, 2022 USD ($) lease agreement	Dec. 29, 2021 USD ($)	Dec. 30, 2020 USD ($)
Other Commitments [Line Items]
Litigation Settlement, Expense						$ 2,566,000
Insurance proceeds						100,000
Officers
Other Commitments [Line Items]
Number of at-will employment agreements | agreement				3
Property Lease Guarantee
Other Commitments [Line Items]
Number of leases assigned to franchisees | lease				3
Latest lease expiration year				2036
Contingent lease obligations, maximum exposure				$ 2,300,000
Contingent lease obligations, maximum exposure, if discounted at estimated pre-tax cost of debt				1,700,000
Chicken Acquisition Corp
Other Commitments [Line Items]
Purchase commitments, estimated obligations				$ 40,900,000
Diep v. Sather
Other Commitments [Line Items]
Litigation amount awarded	$ 625,000
Stay order length		5 months
Litigation Settlement, Expense	$ 156,250
Insurance proceeds					$ 469,000
Janice P. Handlers-Bryman and Michael D. Bryman v. El Pollo Loco, Inc
Other Commitments [Line Items]
Damages paid			$ 2,500,000
Litigation Settlement, Expense						$ 2,500,000