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Stock Compensation Plans (Details 4)	12 Months Ended
Stock Compensation Plans (Details 4)	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Restricted Stock Awards
Fair value of the option component of the ESP Plan
Expected life for the options (in years)	1 year	1 year	1 year
Employee Stock
Fair value of the option component of the ESP Plan
Risk free interest rate	0.11%	0.27%	0.47%
Dividend yield	1.37%	1.21%	1.10%
Volatility factor of the expected market price of the Company's common shares	41.00%	34.00%	54.00%

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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