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Share-Based Compensation Plans (Details)	9 Months Ended
Share-Based Compensation Plans (Details)	Sep. 30, 2012
Black-Scholes option-pricing model
Expected Term (years)	3 years 0 months
Risk-Free Interest Rate	0.39%
Expected Dividend Yield	8.21%
Expected Volatility	21.12%
Expected Forfeiture Rate	1.00%

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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