Stock-Based Compensation Valuation Assumptions (Details) (Options and SSARs [Member], USD $)	12 Months Ended
Dec. 31, 2012 years	Dec. 31, 2011 years	Dec. 31, 2010 years
Options and SSARs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected stock price volatility	64.00%	64.00%	59.00%
Expected dividend yield	0.00%	0.00%	0.00%
Risk-free interest rate	0.70%	2.10%	2.40%
Expected life of options	5.1	5.2	5.1
Weighted average fair value of options and SSARs granted	$ 4.75	$ 5.59	$ 3.73

The period of time an equity-based award is expected to be outstanding. An equity-based award's expected term is generally determined based on, among other factors, the instrument's contractual term and the effects of employees' expected exercise and post-vesting employment termination behavior.

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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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