Stock Compensation Plans (Details 1) (USD $)	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Summary of Stock Options and SARs
Expected volatility	63.30%	65.00%	60.10%
Stock Appreciation Rights (SARs) [Member]
Summary of Stock Options and SARs
Weighted average grant-date fair value, granted	9.68	8.45	6.40
Risk free interest rate	1.74%	2.19%	1.58%
Expected minimum life (in years)	4	4	3.9
Expected maximum life (in years)	5	4.3	4.7
Dividend yield	0.00%	0.00%	0.00%

The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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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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