Condensed Consolidated Statements of Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 23, 2020	Sep. 25, 2019	Sep. 23, 2020	Sep. 25, 2019
Revenue
Total revenue	$ 110,979	$ 112,067	$ 315,746	$ 334,784
Cost of operations
Food and paper cost	24,922	27,512	73,357	82,550
Labor and related expenses	28,756	29,292	83,208	88,140
Occupancy and other operating expenses	23,836	23,844	67,867	70,103
Gain on recovery of insurance proceeds, lost profits	(2,000)		(2,000)
Company restaurant expenses	75,514	80,648	222,432	240,793
General and administrative expenses	9,803	9,539	29,599	30,235
Franchise expenses	7,572	7,006	21,110	20,692
Depreciation and amortization	4,092	4,343	12,629	13,558
Loss on disposal of assets	29	35	156	213
Recovery of securities lawsuits related legal expenses and other insurance claims			(123)	(10,000)
Impairment and closed-store reserves	1,776	367	4,615	1,241
Loss on disposition of restaurants		11		5,062
Total expenses	98,786	101,949	290,418	301,794
Income from operations	12,193	10,118	25,328	32,990
Interest expense, net	770	973	2,583	2,754
Income tax receivable agreement (income) expense	(144)	(197)	26	(120)
Income before provision for income taxes	11,567	9,342	22,719	30,356
Provision for income taxes	1,647	2,940	3,700	8,954
Net income	$ 9,920	$ 6,402	$ 19,019	$ 21,402
Net income per share
Basic (usd per share)	$ 0.28	$ 0.18	$ 0.54	$ 0.57
Diluted (usd per share)	$ 0.28	$ 0.18	$ 0.53	$ 0.56
Weighted-average shares used in computing net income per share
Basic (shares)	35,471,452	35,859,502	34,989,007	37,484,372
Diluted (shares)	36,064,559	36,397,368	35,609,320	38,173,097
Company-operated restaurant revenue
Revenue
Total revenue	$ 97,276	$ 99,052	$ 277,617	$ 296,341
Franchise revenue
Revenue
Total revenue	7,781	7,273	21,562	21,635
Franchise advertising fee revenue
Revenue
Total revenue	$ 5,922	$ 5,742	$ 16,567	$ 16,808