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Stock-Based Compensation (Details) (USD $)	9 Months Ended
Stock-Based Compensation (Details) (USD $)	Sep. 30, 2012	Sep. 30, 2011
Weighted-average assumptions
Weighted average fair value of options granted	$ 11.77	$ 13.26
Risk free interest rate	0.89%	2.00%
Dividend yield	0.00%	0.00%
Volatility factor of the expected market price of the Company's common stock	63.00%	61.00%
Weighted-average expected life of options	5 years	5 years

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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