Common Stock And Share-Based Compensation (Weighted Average Assumptions Used To Estimate The Fair Value Of Grants Issued) (Details)	3 Months Ended
Mar. 31, 2012	Mar. 31, 2011
Common Stock And Share-Based Compensation [Abstract]
Expected volatility	44.00%	41.00%
Expected dividend yield
Expected option term (years)	5	5
Risk-free rate of return, minimum	0.88%	2.19%
Risk-free rate of return, maximum	0.89%	2.30%

The period of time an equity-based award is expected to be outstanding. An equity-based award's expected term is generally determined based on, among other factors, the instrument's contractual term and the effects of employees' expected exercise and post-vesting employment termination behavior.

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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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