Reconciliation of Basic and Diluted Earnings Per Common Share (Detail) - shares shares in Thousands		3 Months Ended
		Nov. 30, 2016	Nov. 30, 2015
Earnings Per Share Disclosure [Line Items]
Weighted average basic common shares outstanding	[1]	29,097	29,391
Dilutive effect of performance based restricted stock units	[2]	57	10
Weighted average diluted common shares outstanding		32,412	32,578
2018 Senior Notes
Earnings Per Share Disclosure [Line Items]
Dilutive effect of convertible notes	[3]	3,258	3,177
2026 Senior Notes
Earnings Per Share Disclosure [Line Items]
Dilutive effect of convertible notes	[4]	0	0

[1] Restricted stock grants and restricted stock units, 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 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 2018 Convertible notes was included as they were considered dilutive under the "if converted" method as further discussed below.

[4] The 2026 Convertible notes were retired during 2016 and therefore were excluded from the three months ended November 30, 2016. The dilutive effect of the 2026 Convertible notes was excluded for the three months ended November 30, 2015 as the average stock price was less than the applicable conversion price and therefore was considered anti-dilutive.