Earnings Per Share - Reconciliation of Shares Used in Computation of Basic and Diluted Earnings Per Common Share (Detail) - shares shares in Thousands		3 Months Ended
		Nov. 30, 2019	Nov. 30, 2018
Earnings Per Share Disclosure [Line Items]
Weighted average basic common shares outstanding	[1]	32,629	32,640
Dilutive effect of restricted stock units	[2]	655	453
Weighted average diluted common shares outstanding		33,284	33,093
2.875% Convertible Senior Notes
Earnings Per Share Disclosure [Line Items]
Dilutive effect of convertible notes	[3]	0	0
2.25% Convertible Senior Notes
Earnings Per Share Disclosure [Line Items]
Dilutive effect of convertible notes	[4]	0

[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.

[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.

[3] The dilutive effect of the 2.875% Convertible notes was excluded for the three months ended November 30, 2019 and 2018 as the average stock price was less than the applicable conversion price and therefore was considered anti-dilutive.

[4] The 2.25% Convertible notes were issued in July 2019. The dilutive effect of the 2.25% Convertible notes was excluded for the three months ended November 30, 2019 as the average stock price was less than the applicable conversion price and therefore was considered anti-dilutive.