Quarterly Financial Information - Summary of Quarterly Unaudited Financial Information (Details) $ / shares in Units, $ in Thousands	3 Months Ended						4 Months Ended		6 Months Ended	12 Months Ended
	Aug. 26, 2020 USD ($) property lease $ / shares	Jun. 03, 2020 USD ($) $ / shares	Mar. 11, 2020 USD ($) $ / shares	Aug. 28, 2019 USD ($) $ / shares	Jun. 05, 2019 USD ($) $ / shares	Mar. 13, 2019 USD ($) $ / shares	Dec. 18, 2019 USD ($) $ / shares	Dec. 19, 2018 USD ($) $ / shares	Mar. 11, 2020 USD ($)	Aug. 26, 2020 USD ($) lease $ / shares	Aug. 28, 2019 USD ($) $ / shares
Revenue from External Customer [Line Items]
Total sales	$ 31,317	$ 18,994	$ 68,562	$ 71,363	$ 74,766	$ 74,424	$ 95,149	$ 102,917		$ 214,022	$ 323,470
Income (loss) from continuing operations	7,674	(24,972)	(3,796)	(9,081)	(5,295)	6,640	(8,327)	(7,483)		(29,421)	(15,219)
Loss from discontinued operations	(5)	(7)	(6)	12	(6)	(8)	(11)	(5)		(29)	(7)
Net loss	$ 7,669	$ (24,979)	$ (3,802)	$ (9,069)	$ (5,301)	$ 6,632	$ (8,338)	$ (7,488)	$ (12,100)	$ (29,450)	$ (15,226)
Net income (loss) per share:
Basic (in dollars per share) | $ / shares	$ 0.25	$ (0.82)	$ (0.13)	$ (0.30)	$ (0.18)	$ 0.22	$ (0.28)	$ (0.25)		$ (0.97)	$ (0.51)
Assuming dilution (in dollars per share) | $ / shares	$ 0.25	$ (0.82)	$ (0.13)	$ (0.30)	$ (0.18)	$ 0.22	$ (0.28)	$ (0.25)		$ (0.97)	$ (0.51)
Costs and Expenses (as a percentage of restaurant sales)
Cost of food	27.70%	29.20%	28.80%	28.50%	28.20%	27.80%	28.70%	27.50%
Payroll and related costs	32.80%	39.70%	39.40%	38.80%	38.10%	37.80%	38.50%	37.90%
Other operating expenses	23.20%	41.70%	16.70%	18.40%	17.50%	17.50%	17.70%	18.10%
Occupancy costs	10.30%	26.70%	6.30%	6.50%	6.10%	6.40%	6.00%	6.40%
Net provision for asset impairments and restaurant closings	$ (4,300)									$ 10,193	$ 5,603
Number of terminated leases | lease	17									17
Net gain on disposition of property and equipment	$ 8,700									$ 11,557	12,832
Number of restaurants related to net gain (loss) on disposition, held for sale | property	5
Number of restaurants related to net gain (loss) on disposition, held for use | property	1
Restaurant sales
Revenue from External Customer [Line Items]
Total sales	$ 25,729	$ 13,832	$ 60,392	$ 62,434	$ 65,611	$ 65,370	$ 83,558	$ 91,098		183,511	284,513
Franchise revenue
Revenue from External Customer [Line Items]
Total sales	576	193	1,158	1,563	1,482	1,421	1,707	2,224		3,634	6,690
Culinary contract services
Revenue from External Customer [Line Items]
Total sales	5,012	4,963	6,998	7,278	7,571	7,543	9,774	9,496		26,747	31,888
Vending revenue
Revenue from External Customer [Line Items]
Total sales	$ 0	$ 6	$ 14	$ 88	$ 102	$ 90	$ 110	$ 99		$ 130	$ 379