Stock-Based Compensation (Schedule of Assumptions Used in Estimate of Fair Value of Stock Option Awards) (Details) (Stock Options [Member])	3 Months Ended
Dec. 31, 2011 years	Dec. 31, 2010 years
Minimum [Member]
Expected term	5.9	5.8
Estimated volatility	48.90%	48.00%
Estimated dividend yield	0.80%	1.10%
Risk-free interest rate	1.30%	1.90%
Maximum [Member]
Expected term	8.5	8.7
Estimated volatility	52.80%	54.00%
Estimated dividend yield	1.10%	1.30%
Risk-free interest rate	1.60%	2.60%

The period of time an equity-based award is expected to be outstanding. An equity-based award's expected term is generally determined based on, among other factors, the instrument's contractual term and the effects of employees' expected exercise and post-vesting employment termination behavior.

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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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