Goodwill and Intangibles - Additional Information (Detail) - USD ($)	4 Months Ended		12 Months Ended
	Aug. 29, 2015	Aug. 30, 2014	Aug. 29, 2015	Aug. 30, 2014	Aug. 31, 2013
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Goodwill impairment charge	$ 0			$ 0	$ 18,300,000
Purchase of intangibles			$ 10,000,000	11,112,000
Impairment charge					$ 4,100,000
Amortization expense of intangible assets			8,700,000	7,100,000
Interamerican Motor Corporation [Member]
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Increased intangible assets related to acquisition			3,600,000
AutoAnything [Member] | Trade Names [Member]
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Impairment charge	0	$ 0
Accumulated impairment	$ 4,100,000	$ 4,100,000	4,100,000	4,100,000
Customer Relationships [Member]
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Purchase of intangibles			$ 10,000,000
Customer Relationship and Technology Assets [Member]
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Purchase of intangibles				$ 30,200,000