Fair Value Measurements - Non-recurring Fair Value Measurements Related to Impaired Property and Equipment (Details) - USD ($)	3 Months Ended		6 Months Ended
	Mar. 14, 2018	Mar. 15, 2017	Mar. 14, 2018	Mar. 15, 2017	Aug. 30, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Nonrecurring Fair Value Measurements, Total Impairments	$ 1,407,000	$ 5,963,000	$ 2,252,000	$ 6,250,000
Property and equipment, net	169,539,000		169,539,000		$ 172,814,000
Goodwill	795,000		795,000		$ 1,068,000
Continuing Operations | Fair Value, Measurements, Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property held for sale	2,331,000	3,213,000	2,331,000	3,213,000
Property held for sale, Total Impairments			(298,000)	(419,000)
Property and equipment related to company-owned restaurants	1,519,000	1,410,000	1,519,000	1,410,000
Property and equipment related to company-owned restaurants, total impairments			(1,116,000)	(5,226,000)
Total Nonrecurring Fair Value Measurements	3,850,000	4,623,000	3,850,000	4,623,000
Total Nonrecurring Fair Value Measurements, Total Impairments			1,687,000	6,182,000
Property held for sale, net	2,600,000	4,800,000	2,600,000	4,800,000
Proceeds from sale of property held-for-sale				1,200,000
Goodwill	273,000	537,000	273,000	537,000
Goodwill, fair value	0	0	0	0
Goodwill, impairment loss			273,000	537,000
Continuing Operations | Fair Value, Measurements, Nonrecurring | Company-owned restaurants
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property and equipment related to company-owned restaurants	1,500,000	1,400,000	1,500,000	1,400,000
Property and equipment related to company-owned restaurants, total impairments			(1,100,000)	(5,200,000)
Property and equipment, net	2,600,000	6,600,000	2,600,000	6,600,000
Continuing Operations | Fair Value, Measurements, Nonrecurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property held for sale	0	0	0	0
Property and equipment related to company-owned restaurants	0	0	0	0
Total Nonrecurring Fair Value Measurements	0	0	0	0
Goodwill, fair value	0	0	0	0
Continuing Operations | Fair Value, Measurements, Nonrecurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property held for sale	0	0	0	0
Property and equipment related to company-owned restaurants	0	0	0	0
Total Nonrecurring Fair Value Measurements	0	0	0	0
Goodwill, fair value	0	0	0	0
Continuing Operations | Fair Value, Measurements, Nonrecurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property held for sale	2,331,000	3,213,000	2,331,000	3,213,000
Property and equipment related to company-owned restaurants	1,519,000	1,410,000	1,519,000	1,410,000
Total Nonrecurring Fair Value Measurements	3,850,000	4,623,000	3,850,000	4,623,000
Goodwill, fair value	$ 0	$ 0	$ 0	$ 0