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Stock-Based Compensation (Details 5) (Stock Appreciation Rights (Sars) [Member])	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Stock Appreciation Rights (Sars) [Member]
Risk free interest rate	1.38%	2.70%
Expected life	7 years	7 years
Expected volatility	29.39%	27.86%
Expected dividend yield	1.84%	1.77%

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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