|
Share-Based Compensation (Details Textual) (USD $)
|
3 Months Ended |
12 Months Ended |
|
Mar. 31, 2013
|
Dec. 31, 2012
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
| Weighted average period of recognition of unrecognized compensation expense |
2 years 6 months 0 days |
|
| Share-Based Compensation (Textual) [Abstract] |
|
|
| Unrecognized compensation expense related to unvested portion of stock options |
$ 10,700,000 |
|
| Intrinsic value of options exercised |
1,300,000 |
|
|
Restricted Stock Awards [Member]
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
| Weighted average period of recognition of unrecognized compensation expense |
2 years 3 months 18 days |
2 years 7 months 6 days |
| Vesting percentage in second anniversary |
50.00% |
|
| Vesting percentage in third year anniversary |
25.00% |
|
| Vesting percentage in fourth year anniversary |
25.00% |
|
| Fair market value of unvested stock |
8,400,000 |
7,700,000 |
|
Restricted Stock Units [Member]
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
| Weighted average period of recognition of unrecognized compensation expense |
2 years 8 months 12 days |
2 years 9 months 18 days |
| Vesting percentage in second anniversary |
50.00% |
|
| Vesting percentage in third year anniversary |
25.00% |
|
| Vesting percentage in fourth year anniversary |
25.00% |
|
| Aggregate intrinsic value of unvested stock |
$ 752,000 |
$ 559,000 |