General - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	5 Months Ended	6 Months Ended
	Feb. 11, 2017	Feb. 11, 2017	Feb. 13, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of reporting periods		Operating results for the twelve and twenty-four weeks ended February 11, 2017 are not necessarily indicative of the results that may be expected for the fiscal year ending August 26, 2017. Each of the first three quarters of AutoZone’s fiscal year consists of 12 weeks, and the fourth quarter consists of 16 or 17 weeks. The fourth quarters for fiscal 2017 and 2016 each have 16 weeks. Additionally, the Company’s business is somewhat seasonal in nature, with the highest sales generally occurring during the months of February through September and the lowest sales generally occurring in the months of December and January.
Increase of earning per share	$ 0.37	$ 0.40
Effective tax rate basis point	3.58%	2.02%
Tax benefit to earning per share	$ 0.43	$ 0.53
Tax reduction to earning per share	$ 0.06	$ 0.13
Excess tax benefit			$ 31.9