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Stock-Based Compensation (Weighted Average Assumptions Used in Calculating Fair Value of Stock Option) (Details)	3 Months Ended
	Mar. 31, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Risk free interest rate	1.30%
Expected life of option in years	6 years 6 months
Expected dividend yield	3.20%
Expected volatility	29.90%

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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