Stock Compensation Plans (Summary of SAR Assumptions) (Details 2) (Stock Appreciation Rights (SARs) [Member], USD $)	1 Months Ended	12 Months Ended
Jan. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Summary of Stock Options and SARs
Weighted average grant-date fair value, granted		8.90	9.68	8.45
Risk-free interest rate		0.79%	1.74%	2.19%
Expected volatility		64.90%	63.30%	65.00%
Dividend yield		0.00%	0.00%	0.00%
Minimum [Member]
Summary of Stock Options and SARs
Weighted average grant-date fair value, granted	$ 5.42
Expected life		4 years	4 years	4 years
Maximum [Member]
Summary of Stock Options and SARs
Weighted average grant-date fair value, granted	$ 8.72
Expected life		5 years	5 years	4 years 3 months

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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