|
Share-Based Compensation (Details)
|
12 Months Ended | ||
|---|---|---|---|
|
Dec. 31, 2011
Y
|
Dec. 31, 2010
Y
|
Dec. 31, 2009
Y
|
|
|
SARS [Member]
|
|||
| Weighted average assumptions used in the calculation of the fair value for service condition awards | |||
| Expected volatility | 46.60% | 48.30% | 48.50% |
| Dividends yield | 1.50% | 1.80% | 5.70% |
| Expected term | 6.2 | 6.4 | 6.5 |
| Risk-free interest rate | 1.90% | 2.40% | 2.30% |
|
Independent Director's SARS [Member]
|
|||
| Weighted average assumptions used in the calculation of the fair value for service condition awards | |||
| Expected volatility | 49.40% | 48.20% | 48.60% |
| Dividends yield | 1.50% | 1.70% | 5.80% |
| Expected term | 3.8 | 3.8 | 3.8 |
| Risk-free interest rate | 1.00% | 1.30% | 1.40% |