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Share-based Compensation Share-based Compensation (Assumptions Used in Estimating Fair Value of Stock Options and SARs) (Details) (Stock Options and SARs [Member], USD $)	12 Months Ended
	Aug. 31, 2012	Aug. 31, 2011	Aug. 31, 2010
Stock Options and SARs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	0.43%	0.59%	0.86%
Expected life, years	3 years	2 years	2 years
Expected volatility	59.00%	56.00%	80.00%
Expected dividend yield	4.14%	2.85%	3.42%
Weighted average grant-date fair value per share	$ 3.67	$ 4.63	$ 5.43

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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