Document and Entity Information - shares
9 Months Ended
Sep. 25, 2019
Oct. 25, 2019
Document And Entity Information [Abstract]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Sep. 25, 2019  
Document Fiscal Year Focus 2019  
Document Fiscal Period Focus Q3  
Entity Registrant Name El Pollo Loco Holdings, Inc.  
Entity Central Index Key 0001606366  
Current Fiscal Year End Date --12-25  
Entity Filer Category Accelerated Filer  
Emerging Growth Company true  
Small Business Entity true  
Entity Ex Transition Period false  
Entity Current Reporting Status Yes  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   34,882,844