|
Share-based Compensation (Details) (Stock options, USD $)
|
3 Months Ended | |
|---|---|---|
|
Mar. 31, 2012
year
|
Mar. 31, 2011
year
|
|
|
Stock options
|
||
| Fair value assumptions used in computation of grant date fair value of options | ||
| Number of options granted (in shares) | 40,000 | 12,000 |
| Grant date fair value of options granted per share (in dollars per share) | $ 8.16 | $ 17.08 |
| Weighted average exercise price of options granted (in dollars per share) | $ 14.27 | $ 29.62 |
| Volatility (as a percent) | 61.00% | 59.00% |
| Risk free interest rate (as a percent) | 1.40% | 2.70% |
| Expected term (in years) | 6.3 | 6.3 |