Earnings Per Share - Reconciliation of Shares Used in Computation of Basic and Diluted Earnings Per Common Share (Detail) - shares shares in Thousands		12 Months Ended
		Aug. 31, 2021	Aug. 31, 2020	Aug. 31, 2019
Earnings Per Share Disclosure [Line Items]
Weighted average basic common shares outstanding	[1]	32,648	32,670	32,615
Dilutive effect of restricted stock units	[2]	1,017	771	550
Weighted average diluted common shares outstanding		33,665	33,441	33,165

[1] Restricted stock grants and restricted stock units that are considered participating securities, including some grants subject to certain performance criteria, are included in weighted average basic common shares outstanding when the Company is in a net earnings position. No restricted stock or restricted stock units were anti-dilutive for the years ended August 31, 2021, 2020 and 2019.

[2] Restricted stock units that are not considered participating securities and restricted stock units subject to performance criteria, for which actual levels of performance above target have been achieved, are included in weighted average diluted common shares outstanding when the Company is in a net earnings position.