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Stock Options and Restricted Stock Stock Options, Valuation Assumptions (Details)	6 Months Ended	12 Months Ended
	Jun. 30, 2012	Dec. 31, 2011
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Risk-free interest rate	1.00%	1.80%
Expected volatility	44.60%	43.80%
Expected life (in years)	6 years	6 years
Dividend yield	0.00%	0.00%

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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