Commitments and Contingencies - Additional Information (Details)		3 Months Ended	12 Months Ended
	Sep. 10, 2021 USD ($)	Sep. 23, 2020 USD ($)	Dec. 29, 2021 USD ($) agreement lease	Dec. 30, 2020 USD ($)	Dec. 25, 2019 USD ($)
Other Commitments [Line Items]
Litigation Settlement, Expense			$ 0	$ 2,566,000	$ 0
Insurance proceeds				100,000
Loss contingency accrual, reduction due to payment by affiliates			$ 100,000
Officers
Other Commitments [Line Items]
Number of at-will employment agreements | agreement			3
Property Lease Guarantee
Other Commitments [Line Items]
Accrual associated with loss contingencies				100,000
Number of leases assigned to franchisees | lease			4
Latest lease expiration year			2036
Contingent lease obligations, maximum exposure			$ 2,600,000
Contingent lease obligations, maximum exposure, if discounted at estimated pre-tax cost of debt			2,400,000
Chicken Acquisition Corp
Other Commitments [Line Items]
Purchase commitments, estimated obligations			38,700,000
Janice P. Handlers-Bryman and Michael D. Bryman v. El Pollo Loco, Inc
Other Commitments [Line Items]
Litigation Settlement, Expense		$ 2,500,000		$ 2,500,000
Diep action
Other Commitments [Line Items]
Proposed settlement payment	$ 625,000
Litigation Settlement, Expense	$ 156,250
Insurance proceeds			$ 469,000