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Stockholders' Equity (Weighted Average Assumptions Used To Estimate The Fair Value Of Stock Option Grants) (Details)	12 Months Ended
	Aug. 31, 2012	Aug. 31, 2011	Aug. 31, 2010
Stockholders' Equity [Abstract]
Expected term (years)	4 years 10 months 24 days	4 years 8 months 12 days	4 years 6 months
Expected volatility	48.00%	46.00%	45.00%
Risk-free interest rate	0.80%	2.00%	2.20%
Expected dividend yield	0.00%	0.00%	0.00%

The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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