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Stock-Based Compensation Plans (Details) (Stock Options [Member])	3 Months Ended
	Mar. 31, 2013
Stock Options [Member]
Valuation of stock options granted
Expected dividend yield	0.00%
Expected volatility	31.90%
Risk-free interest rate	0.87%
Expected life in years	7 years 3 months 0 days

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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