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Common Stock and Stock Plans, Weighted-Average Per Share Fair Value of Options Granted (Details) (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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| Weighted-Average per Share Fair Value of Options Granted and the Assumptions Used [Abstract] | |||
| Per share fair value of options granted | $ 2.79 | $ 3.78 | $ 6.11 |
| Expected Volatility | 29.20% | 32.70% | 44.30% |
| Expected dividends | $ 0.68 | $ 0.32 | $ 0.20 |
| Expected term (in years) | 0 years 8 months 12 days | 1 year 0 months 0 days | 1 year 3 months 18 days |
| Risk-free interest rate | 0.10% | 0.20% | 0.60% |
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- Details
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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 weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
The estimated amount of dividends per share to be paid to holders of the underlying shares (expected dividends) over the option's term. Dividends are taken into account because payment of dividends to shareholders reduces the fair value of the underlying shares, and option holders generally do not receive dividends. No definition available.
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