Condensed Consolidated Statements of Operations (Unaudited) - Parenthetical - USD ($) $ in Thousands	3 Months Ended
Mar. 27, 2019	Mar. 28, 2018
Income Statement [Abstract]
Interest Income	$ 9	$ 8

Investment Income, Bank Earning Allowance And Miscellaneous Interest

No definition available.

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Namespace Prefix:	loco_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration