Annual report pursuant to Section 13 and 15(d)

Guarantor Subsidiaries - Additional Information (Detail)

v2.4.0.8
Guarantor Subsidiaries - Additional Information (Detail) (USD $)
Aug. 31, 2012
Convertible Notes
2% Converitble Notes
Nov. 30, 2003
Convertible Notes
2% Converitble Notes
Aug. 31, 2014
Senior Notes
5.625% Senior Notes
Aug. 31, 2013
Senior Notes
5.625% Senior Notes
Aug. 31, 2012
Senior Notes
5.625% Senior Notes
Apr. 16, 2012
Senior Notes
5.625% Senior Notes
Aug. 31, 2012
Senior Notes
6.875% Senior Notes
Apr. 16, 2012
Senior Notes
6.875% Senior Notes
Debt Instrument [Line Items]                
Long-term debt   $ 150,000,000.0 $ 300,000,000     $ 300,000,000.0   $ 250,000,000
Debt instrument, interest rate 2.00% 2.00% 5.625% 5.625% 5.625% 5.625% 6.875% 6.875%