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Stockholders’ Equity And Stock-Based Compensation (Schedule Of Employee Stock Purchase Plan) (Details)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Stockholders’ Equity And Stock-Based Compensation [Abstract]
Dividend expense yield	0.50%	0.40%	0.40%
Expected life (in months)	3 months	3 months	3 months
Expected volatility	40.00%	44.00%	25.00%
Risk-free interest rate	0.10%	0.10%	0.10%

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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