Earnings before Income Taxes, Including both Continuing and Discontinued Operations (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Aug. 31, 2012	Aug. 31, 2011	Aug. 31, 2010
Income Tax Examination [Line Items]
Earnings before income taxes, including both continuing and discontinued operations	$ 120,314	$ 142,221	$ 48,011
Domestic Tax Authority
Income Tax Examination [Line Items]
Earnings before income taxes, including both continuing and discontinued operations	79,467	40,096	14,967
Foreign Tax Authority
Income Tax Examination [Line Items]
Earnings before income taxes, including both continuing and discontinued operations	$ 40,847	$ 102,125	$ 33,044