Segment Reporting (Reconciliation Of Net Income To Restaurant-Level EBITDA) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 21, 2017	Mar. 22, 2016
Segment Reporting [Abstract]
Net income	$ 3,310	$ 5,411
Income tax expense	1,086	2,437
Income before income taxes	4,396	7,848
Interest expense, net of capitalized interest	10	31
Other	2
Operating income	4,408	7,879
Pre-opening costs	389	94
General and administrative costs	6,311	5,750
Consulting project costs	2,036
Lease termination and closing costs	(2)	21
Depreciation and amortization	4,816	4,285
Restaurant-level EBITDA	$ 17,958	$ 18,029