Condensed Consolidated Statements of Operations - Unaudited - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 25, 2019	Jun. 26, 2018	Jun. 25, 2019	Jun. 26, 2018
Income Statement [Abstract]
Revenues	$ 131,687	$ 75,718	$ 252,068	$ 149,064
Costs and expenses:
Cost of sales	35,873	21,537	69,165	42,754
Restaurant operating expenses (excluding depreciation and amortization shown separately below)	65,261	36,337	127,399	72,558
Marketing and advertising costs	2,260	1,666	4,512	3,196
Pre-opening costs	1,301	1,403	4,050	2,549
General and administrative costs	17,117	7,988	33,489	15,778
Donations	163	16	195	58
Consulting project costs	3,450	621	7,954	854
Acquisition costs	0	4,338	0	4,946
Reorganization severance	480	0	777	113
Lease termination and closing costs	(1,754)	589	1,154	591
Depreciation and amortization	8,144	4,237	15,795	8,372
Total costs and expenses	132,295	78,732	264,490	151,769
Operating loss	(608)	(3,014)	(12,422)	(2,705)
Other income (expense), net:
Interest, net of capitalized interest	(8,409)	(510)	(16,129)	(814)
Other	(32)	(50)	(19)	(49)
Loss before income taxes	(9,049)	(3,574)	(28,570)	(3,568)
Income tax benefit	(2,651)	(2,182)	(3,845)	(2,181)
Loss from continuing operations	(6,398)	(1,392)	(24,725)	(1,387)
(Loss) income from discontinued operations, net of tax	0	(170)	0	225
Net loss	$ (6,398)	$ (1,562)	$ (24,725)	$ (1,162)
Net loss per average common share outstanding — basic and diluted
Loss from continuing operations (in usd per share)	$ (0.19)	$ (0.07)	$ (0.74)	$ (0.07)
(Loss) income from discontinued operations (in usd per share)	0.00	(0.01)	0.00	0.01
Net loss (in usd per share)	$ (0.19)	$ (0.08)	$ (0.74)	$ (0.06)
Weighted-average number of common shares outstanding:
Basic (in shares)	33,417	20,377	33,387	20,347
Diluted (in shares)	33,417	20,377	33,387	20,347