Segment Reporting (Reconciliation Of Net Income To Restaurant-Level EBITDA) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 13, 2017	Jun. 14, 2016	Jun. 13, 2017	Jun. 14, 2016
Segment Reporting [Abstract]
Net income	$ 2,090	$ 4,444	$ 5,400	$ 9,855
Income tax expense	824	1,852	1,910	4,289
Income before income taxes	2,914	6,296	7,310	14,144
Interest expense, net of capitalized interest	9	24	19	55
Other	10	5	11	5
Operating income	2,933	6,325	7,340	14,204
Pre-opening costs	1,619	591	2,008	685
General and administrative costs	5,921	6,030	12,076	11,780
Consulting project costs	597	0	2,633	0
Reorganization severance	563	0	719	0
Lease termination and closing costs	540	20	538	41
Depreciation and amortization	4,997	4,163	9,813	8,448
Insurance settlements	(308)	0	(348)	0
Restaurant-level EBITDA	$ 16,862	$ 17,129	$ 34,779	$ 35,158