Goodwill and Intangibles - Additional Information (Detail) - USD ($)	4 Months Ended			12 Months Ended
	Aug. 25, 2018	Feb. 10, 2018	Aug. 26, 2017	Aug. 25, 2018	Aug. 26, 2017
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Goodwill impairment charge	$ 0		$ 0
Accumulated goodwill impairment	107,500,000		18,300,000	$ 107,500,000	$ 18,300,000
Amortization expense of intangible assets				5,100,000	8,500,000
Trade Name [Member] | AutoAnything's and Interamerican Motor Corporation [Member]
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Impairment charge		$ 26,900,000
Accumulated impairment	$ 31,000,000		$ 4,100,000	$ 31,000,000	$ 4,100,000