Reconciliation of Basic and Diluted Earnings Per Common Share (Detail) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	May 31, 2013		May 31, 2012		May 31, 2013		May 31, 2012
Earnings Per Share Disclosure [Line Items]
Weighted average basic common shares outstanding	26,619	[1],[2]	26,981	[1],[2]	26,510	[1],[2]	26,378	[1],[2]
Dilutive effect of warrants		[3]	836	[3]		[3]	1,217	[3]
Dilutive effect of restricted stock units		[2],[3]		[2],[3]		[2],[3]		[2],[3]
Dilutive effect of convertible notes		[3],[4]	6,045	[3],[4]		[3],[4]	6,045	[3],[4]
Weighted average diluted common shares outstanding	26,619		33,862		26,510		33,640

[1] Restricted stock grants are treated as outstanding when issued and are included in weighted average basic common shares outstanding when the Company is in a net earnings position. Shares outstanding exclude shares of unvested restricted stock for the three and nine months ended May 31, 2013 due to a net loss.

[2] Restricted stock units were granted during the three months ended May 31, 2013. Restricted stock units are not included in weighted average basic common shares outstanding. The dilutive effect of restricted stock units is included in the weighted average diluted common shares outstanding when the Company is in a net earnings position.

[3] The dilutive effect of common stock equivalents is excluded from the share calculations for the three and nine months ended May 31, 2013 due to a net loss.

[4] The dilutive effect of the 2018 Convertible notes are included for the three and nine months ended May 31, 2012 as they were considered dilutive under the "if converted" method as further discussed below. The dilutive effect of the 2026 Convertible notes was excluded from the share calculations as the stock price for each period presented was less than the initial conversion price of $48.05 and therefore considered anti-dilutive.