Other Information Pertaining to Option Activity (Detail) (USD $) In Thousands, except Per Share data | 12 Months Ended | ||
|---|---|---|---|
Aug. 31, 2011 | Aug. 31, 2010 | Aug. 31, 2009 | |
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Weighted average grant-date fair value of stock options granted | $ 13.73 | $ 11.65 | $ 12.54 |
| Total fair value of stock options vested | $ 3,757 | $ 3,928 | $ 14,506 |
| Total intrinsic value of stock options exercised | $ 450,956 | $ 177,721 | $ 83,089 |