Shareholders' Equity (Fair Value Assumptions Used For Stock Options Grants) (Details)	12 Months Ended
Dec. 31, 2011 years	Dec. 31, 2010 years	Dec. 31, 2009 years
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life in years	5.14	5.08	5.05
Expected volatility	43.65%	42.72%	47.11%
Expected dividend yield	0.00%	0.00%	0.00%
Risk-free interest rate	1.45%	2.06%	2.33%
Black-Scholes Option Pricing Model [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life in years	4.99	6.51	6.45
Expected volatility	43.34%	44.29%	46.86%
Expected dividend yield	0.00%	0.00%	0.00%
Risk-free interest rate	0.19%	2.08%	2.38%

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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