Impairment of Long-Lived Assets, Store Closings, Discontinued Operations and Property Held for Sale - Impairment Charges to Income from Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Aug. 26, 2020	Aug. 26, 2020	Aug. 28, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
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)
Disposal Group, Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net provision for asset impairments and restaurant closings		10,193	5,603
Net gain on disposition of property and equipment		(11,557)	(12,832)
Total		$ (1,364)	$ (7,229)
Effect on EPS:
Basic (in dollars per share)		$ 0.05	$ 0.24
Assuming dilution (in dollars per share)		$ 0.05	$ 0.24