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Note 2. Long-Term Incentive Plans (Detail) - Stock Option Fair Value Assumptions (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Expected volatility	76.23%	69.82%
Risk-free interest rate	1.06%	1.48%
Expected dividend yield	0.00%	0.00%
Expected life (in years)	6 years	6 years
Estimated fair value per option granted (in Dollars per share)	$ 0.87	$ 1.01

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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