Description of Business - Additional Information (Detail)	12 Months Ended
	Dec. 28, 2016 Restaurants Segment	Sep. 28, 2016 Restaurants	Jun. 29, 2016 Restaurants	Mar. 30, 2016 Restaurants	Dec. 30, 2015 Restaurants	Sep. 30, 2015 Restaurants	Jul. 01, 2015 Restaurants	Apr. 01, 2015 Restaurants	Sep. 24, 2014 Restaurants
Description Of Business [Line Items]
Number of restaurants									6
Date of reorganization	Apr. 22, 2014
Reorganization terms	(“Old Holdings”) entered into the following reorganization transactions: (i) Old Holdings merged with and into CSC with CSC continuing as the surviving corporation; (ii) CSC merged with and into CAC with CAC continuing as the surviving corporation and (iii) CAC renamed itself El Pollo Loco Holdings, Inc.
Restricted dividend payments, description	Under the 2014 Revolver, Holdings may not make certain payments such as cash dividends, except that it may, inter alia, (i) pay up to $1.0 million per year to repurchase or redeem qualified equity interests of Holdings held by past or present officers, directors, or employees (or their estates) of the Company upon death, disability, or termination of employment, (ii) pay under its income tax receivable agreement (the “TRA”), and, (iii) so long as no default or event of default has occurred and is continuing, (a) make non-cash repurchases of equity interests in connection with the exercise of stock options by directors and officers, provided that those equity interests represent a portion of the consideration of the exercise price of those stock options, (b) pay up to $2.5 million per year pursuant to stock option plans, employment agreements, or incentive plans, (c) make up to $5.0 million in other restricted payments per year, and (d) make other restricted payments, provided that such payments would not cause, in each case, on a pro forma basis, (x) its lease-adjusted consolidated leverage ratio to equal or exceed 4.25 times and (y) its consolidated fixed charge coverage ratio to be less than 1.75 times.
Number of operating segments | Segment	1
Chicken Acquisition Corp [Member]
Description Of Business [Line Items]
Ownership interest	43.50%
Philippines [Member]
Description Of Business [Line Items]
Number of restaurants	2
Entity Operated Units [Member]
Description Of Business [Line Items]
Number of restaurants	201	193	188	188	186	175	174	173
Entity Operated Units [Member] | The Greater Los Angeles Area [Member]
Description Of Business [Line Items]
Number of restaurants	137
Franchised Units [Member]
Description Of Business [Line Items]
Number of restaurants	259	253	251	248	247	245	244	243
Franchised Units [Member] | The Greater Los Angeles Area [Member]
Description Of Business [Line Items]
Number of restaurants	138