Reconciliation of Basic and Diluted Earnings Per Common Share (Detail) In Thousands, unless otherwise specified	3 Months Ended
	Nov. 30, 2014		Nov. 30, 2013
Earnings Per Share Disclosure [Line Items]
Weighted average basic common shares outstanding	27,665	[1]	28,417	[1]
Weighted average diluted common shares outstanding	33,713		34,462
2018 Senior Notes
Earnings Per Share Disclosure [Line Items]
Dilutive effect of convertible notes	6,044	[2]	6,045	[2]
2026 Senior Notes
Earnings Per Share Disclosure [Line Items]
Dilutive effect of convertible notes	4	[3]

[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] The dilutive effect of the 2018 Convertible notes was included for the three months ended November 30, 2014 and 2013 as they were considered dilutive under the "if converted" method as further discussed below.

[3] The dilutive effect of the 2026 Convertible notes was included for the three months ended November 30, 2014 as the average stock price was greater than $48.05. The effect of the 2026 Convertible notes was excluded for the three months ended November 30, 2013 as the average stock price was less than $48.05 and therefore was considered anti-dilutive.