Cover Page - shares	3 Months Ended
	Mar. 24, 2020	Apr. 27, 2020
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 24, 2020
Document Transition Report	false
Entity Registrant Name	DEL TACO RESTAURANTS, INC.
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		37,080,960
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q1
Entity Central Index Key	0001585583
Current Fiscal Year End Date	--12-29