Reportable Segments - Segment Reporting Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 13, 2019	Mar. 14, 2018	Mar. 13, 2019	Mar. 14, 2018
Sales:
Total revenue	$ 74,423	$ 81,793	$ 177,341	$ 195,290
Segment level profit:
Segment level profit	9,007	6,987	20,865	20,023
Depreciation and amortization:
Depreciation and amortization	3,222	3,998	8,126	9,351
Capital expenditures:
Purchases of property and equipment	662	3,705	1,781	8,030
Income (loss) before income taxes and discontinued operations
Segment level profit	9,007	6,987	20,865	20,023
Opening costs	(11)	(331)	(44)	(406)
Depreciation and amortization	(3,222)	(3,998)	(8,126)	(9,351)
Selling, general and administrative expenses	(9,017)	(9,188)	(20,240)	(20,712)
Provision for asset impairments and restaurant closings	(1,195)	(1,407)	(2,422)	(2,252)
Net gain (loss) on disposition of property and equipment	12,651	204	12,501	(18)
Interest income	19	5	19	11
Interest expense	(1,554)	(545)	(3,269)	(1,194)
Other income, net	55	194	86	309
Income (loss) before income taxes and discontinued operations	6,733	(8,079)	(630)	(13,590)
Company-owned restaurants
Sales:
Total revenue	65,459	74,503	156,658	179,228
Segment level profit:
Segment level profit	7,007	5,743	16,233	16,826
Income (loss) before income taxes and discontinued operations
Segment level profit	7,007	5,743	16,233	16,826
Culinary contract services
Sales:
Total revenue	7,543	5,889	17,039	12,774
Segment level profit:
Segment level profit	826	212	1,507	765
Income (loss) before income taxes and discontinued operations
Segment level profit	826	212	1,507	765
Franchise operations
Sales:
Total revenue	1,421	1,401	3,644	3,288
Segment level profit:
Segment level profit	1,174	1,032	3,125	2,432
Income (loss) before income taxes and discontinued operations
Segment level profit	1,174	1,032	3,125	2,432
Operating Segments | Company-owned restaurants
Depreciation and amortization:
Depreciation and amortization	2,613	3,319	7,004	7,772
Capital expenditures:
Purchases of property and equipment	498	2,993	1,562	6,417
Income (loss) before income taxes and discontinued operations
Depreciation and amortization	(2,613)	(3,319)	(7,004)	(7,772)
Operating Segments | Culinary contract services
Depreciation and amortization:
Depreciation and amortization	24	18	46	37
Capital expenditures:
Purchases of property and equipment	(44)	22	10	130
Income (loss) before income taxes and discontinued operations
Depreciation and amortization	(24)	(18)	(46)	(37)
Operating Segments | Franchise operations
Depreciation and amortization:
Depreciation and amortization	177	178	413	414
Income (loss) before income taxes and discontinued operations
Depreciation and amortization	(177)	(178)	(413)	(414)
Corporate
Depreciation and amortization:
Depreciation and amortization	408	483	663	1,128
Capital expenditures:
Purchases of property and equipment	208	690	209	1,483
Income (loss) before income taxes and discontinued operations
Depreciation and amortization	(408)	(483)	(663)	(1,128)
Vending revenue
Sales:
Total revenue	90	$ 151	190	$ 294
Gift Cards, net of discounts
Income (loss) before income taxes and discontinued operations
Amortization of discounts, net of gift card breakage	$ 100		$ 244