Equity and Stock Based-Compensation (Details) (USD $)	12 Months Ended
Dec. 31, 2011 Y	Dec. 31, 2010 Y	Dec. 31, 2009 Y
Assumptions
Risk-free interest rate	2.37%	2.63%	1.94%
Assumed dividend yield	2.95%	5.50%	6.00%
Assumed lives of option awards (in years)	5.30	5.40	6.07
Assumed volatility	65.30%	64.20%	47.40%
Result
Weighted average fair value of options granted	$ 3.90	$ 2.68	$ 2.18

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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