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Stock Options (Details 3) (Stock Options [Member], USD $)
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12 Months Ended | ||
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Dec. 31, 2012
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Dec. 31, 2011
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Dec. 31, 2010
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Stock Options [Member]
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| Risk-free interest rate | 0.80% | 2.30% | |
| Risk-free interest rate, Maximum | 0.90% | ||
| Risk-free interest rate, Minimum | 1.50% | ||
| Expected option term | 4 years 6 months | 4 years 6 months | 4 years 6 months |
| Expected price volitility | 62.00% | 55.00% | 39.00% |
| Dividend yield | 0.00% | 0.00% | 0.00% |
| Weighted average grant date fair value (in dollars per share) | $ 22.36 | $ 10.67 | $ 6.13 |
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- Definition
The weighted average grant date fair value in fair value assumptions of compensation cost. No definition available.
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- Definition
The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Expected term of share-based compensation awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
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. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
The risk-free interest rate assumption that is used in valuing an option on its own shares. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
The maximum risk-free interest rate assumption that is used in valuing an option on its own shares. No definition available.
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- Definition
The minimum risk-free interest rate assumption that is used in valuing an option on its own shares. No definition available.
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