Reportable Segments - Segment Reporting Information (Details) - USD ($) $ in Thousands	3 Months Ended						4 Months Ended		12 Months Ended
	Aug. 26, 2020	Jun. 03, 2020	Mar. 11, 2020	Aug. 28, 2019	Jun. 05, 2019	Mar. 13, 2019	Dec. 18, 2019	Dec. 19, 2018	Aug. 26, 2020	Aug. 28, 2019	Aug. 29, 2019
Sales:
TOTAL SALES	$ 31,317	$ 18,994	$ 68,562	$ 71,363	$ 74,766	$ 74,424	$ 95,149	$ 102,917	$ 214,022	$ 323,470
Segment level profit:
Segment level profit									14,205	36,276
Depreciation and amortization:
Depreciation and amortization									11,514	13,998
Total assets:
Assets	177,403			186,000					177,403	186,000	$ 212,846
Intangible assets	29,642			29,632					29,642	29,632
Capital expenditures:
Capital expenditures									2,120	3,987
Loss before income taxes and discontinued operations:
Segment level profit									14,205	36,276
Opening costs									(14)	(56)
Depreciation and amortization									(11,514)	(13,998)
Selling, general and administrative expenses									(24,571)	(34,685)
Other charges									(3,401)	(3,764)
Net provision for asset impairments and restaurant closings	4,300								(10,193)	(5,603)
Net gain on disposition of property and equipment	8,700								11,557	12,832
Interest income									60	30
Interest expense									(6,388)	(5,977)
Other income, net									1,195	195
Loss before income taxes and discontinued operations									(29,064)	(14,750)
Vending revenue
Sales:
TOTAL SALES	0	$ 6	$ 14	88	$ 102	$ 90	$ 110	$ 99	130	379
Total assets:
Vending revenue									130	379
Luby's cafeterias
Sales:
TOTAL SALES									149,691	214,074
Segment level profit:
Segment level profit									12,087	25,423
Loss before income taxes and discontinued operations:
Segment level profit									12,087	25,423
Fuddruckers restaurants
Sales:
TOTAL SALES									32,428	67,710
Segment level profit:
Segment level profit									(2,196)	2,702
Loss before income taxes and discontinued operations:
Segment level profit									(2,196)	2,702
Cheeseburger in Paradise restaurants
Sales:
TOTAL SALES									1,522	3,108
Segment level profit:
Segment level profit									(308)	(240)
Loss before income taxes and discontinued operations:
Segment level profit									(308)	(240)
Culinary contract services
Sales:
TOTAL SALES									26,747	31,888
Segment level profit:
Segment level profit									2,529	3,334
Loss before income taxes and discontinued operations:
Segment level profit									2,529	3,334
Fuddruckers franchise operations
Sales:
TOTAL SALES									3,634	6,690
Segment level profit:
Segment level profit									2,093	5,057
Loss before income taxes and discontinued operations:
Segment level profit									2,093	5,057
Fuddruckers franchise operations | Trade Names
Total assets:
Intangible assets	6,900			7,500					6,900	7,500
Fuddruckers franchise operations | Royalty intangibles
Total assets:
Intangible assets	8,400			9,200					8,400	9,200
Company-owned restaurants | Fuddruckers trade name, Cheeseburger in Paradise liquor licenses, and Jimmy Buffet intangibles
Total assets:
Intangible assets	34			46					34	46
Operating Segments | Luby's cafeterias
Depreciation and amortization:
Depreciation and amortization									7,598	8,886
Total assets:
Assets	90,349			107,287					90,349	107,287
Capital expenditures:
Capital expenditures									1,841	3,195
Loss before income taxes and discontinued operations:
Depreciation and amortization									(7,598)	(8,886)
Operating Segments | Fuddruckers restaurants
Depreciation and amortization:
Depreciation and amortization									1,507	2,844
Total assets:
Assets	26,502			25,725					26,502	25,725
Capital expenditures:
Capital expenditures									148	513
Loss before income taxes and discontinued operations:
Depreciation and amortization									(1,507)	(2,844)
Operating Segments | Cheeseburger in Paradise restaurants
Depreciation and amortization:
Depreciation and amortization									77	117
Total assets:
Assets	164			829					164	829
Capital expenditures:
Capital expenditures									34	16
Loss before income taxes and discontinued operations:
Depreciation and amortization									(77)	(117)
Operating Segments | Culinary contract services
Depreciation and amortization:
Depreciation and amortization									34	82
Total assets:
Assets	4,744			6,703					4,744	6,703
Loss before income taxes and discontinued operations:
Depreciation and amortization									(34)	(82)
Operating Segments | Fuddruckers franchise operations
Depreciation and amortization:
Depreciation and amortization									298	767
Total assets:
Assets	8,973			10,034					8,973	10,034
Capital expenditures:
Capital expenditures									9	0
Loss before income taxes and discontinued operations:
Depreciation and amortization									(298)	(767)
Corporate
Depreciation and amortization:
Depreciation and amortization									2,000	1,302
Total assets:
Assets	$ 46,671			$ 35,422					46,671	35,422
Capital expenditures:
Capital expenditures									88	263
Loss before income taxes and discontinued operations:
Depreciation and amortization									$ (2,000)	$ (1,302)