Commitments and Contingencies - Additional Information (Details)		3 Months Ended	9 Months Ended
	Nov. 06, 2018 USD ($)	Sep. 25, 2019 USD ($) lawsuit	Sep. 25, 2019 USD ($) lawsuit agreement lease	Sep. 26, 2018 USD ($)	Dec. 26, 2018 USD ($)
Other Commitments [Line Items]
Date of class action filed in court			On or about February 24, 2014
Number of lawsuits consolidated | lawsuit		2	2
Professional Fees	$ 1,391,702.50
Accrual associated with loss contingencies		$ 0	$ 0
Employment agreement expense		73,221.86	$ 473,222	$ 800,000
Officers
Other Commitments [Line Items]
Number of at-will employment agreements | agreement			4
Property Lease Guarantee
Other Commitments [Line Items]
Number of leases assigned to franchisees | lease			5
Latest lease expiration year			2036
Contingent lease obligations, maximum exposure		2,100,000	$ 2,100,000
Contingent lease obligations, maximum exposure, if discounted at estimated pre-tax cost of debt		1,800,000	1,800,000
Chicken
Other Commitments [Line Items]
Purchase commitments, estimated obligations		$ 4,200,000	4,200,000
Impact Damages
Other Commitments [Line Items]
Value of damages awarded			4,356,600
Lost Opportunity Damages
Other Commitments [Line Items]
Value of damages awarded			4,481,206
Total Damages
Other Commitments [Line Items]
Value of damages awarded			$ 8,837,806
Daniel Turocy, et al. and Ron Huston et al v. El Pollo Loco Holdings, Inc., et al [Member]
Other Commitments [Line Items]
Accrual associated with loss contingencies					$ 20,000,000