Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 27, 2022	Sep. 28, 2021	Sep. 27, 2022	Sep. 28, 2021
Revenue:
Total revenue	$ 129,381	$ 125,126	$ 373,010	$ 360,352
Restaurant operating costs (exclusive of depreciation and amortization shown separately below):
Other restaurant operating costs	22,709	21,529	67,367	62,816
General and administrative	11,596	12,187	36,180	36,094
Depreciation and amortization	5,826	5,571	17,310	16,734
Pre-opening	337	125	1,098	346
Restaurant impairments, closure costs and asset disposals	1,672	1,126	5,032	2,747
Total costs and expenses	127,852	119,806	375,678	350,187
Income (loss) from operations	1,529	5,320	(2,668)	10,165
Interest expense, net	735	594	1,661	1,714
Income (loss) before taxes	794	4,726	(4,329)	8,451
(Benefit from) provision for income taxes	(1)	29	(40)	48
Net income (loss)	$ 795	$ 4,697	$ (4,289)	$ 8,403
Earnings (loss) per Class A and Class B common stock, combined
Basic (USD per share)	$ 0.02	$ 0.10	$ (0.09)	$ 0.19
Diluted (USD per share)	$ 0.02	$ 0.10	$ (0.09)	$ 0.18
Weighted average shares of Class A and Class B common stock outstanding, combined:
Basic (in shares)	46,010,824	45,635,455	45,872,893	45,414,332
Diluted (in shares)	46,197,511	46,382,509	45,872,893	46,134,994
Restaurant revenue
Revenue:
Total revenue	$ 126,638	$ 123,094	$ 364,873	$ 354,553
Restaurant operating costs (exclusive of depreciation and amortization shown separately below):
Restaurant operating costs	35,528	30,946	101,963	88,728
Franchising royalties and fees, and other
Revenue:
Total revenue	2,743	2,032	8,137	5,799
Labor
Restaurant operating costs (exclusive of depreciation and amortization shown separately below):
Restaurant operating costs	39,049	36,896	113,370	108,128
Occupancy
Restaurant operating costs (exclusive of depreciation and amortization shown separately below):
Restaurant operating costs	$ 11,135	$ 11,426	$ 33,358	$ 34,594