Incentive Award Plan and Stock Option Plan - Narrative (Details) - USD ($)
$ in Millions |
3 Months Ended |
Mar. 31, 2015 |
Mar. 31, 2014 |
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
| Number of shares authorized under plan (in shares) |
2,000,000
|
|
| General and Administrative Expense |
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
| Stock-based compensation expense |
$ 3.8
|
$ 2.5
|
| Non-vested shares of restricted stock |
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
| Deferred compensation expense |
$ 4.3
|
|
| Outstanding non vested restricted shares (in shares) |
1,300,000
|
|
| Non-vested shares of restricted stock | Directors Officers And Employees |
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
| Grants in period (in shares) |
400,000
|
|
| Performance Shares |
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
| Shares of common stock available for issuance (in shares) |
236,826
|
|
| Stock-based compensation expense |
$ 3.5
|
|
| Potential grants in period based on total shareholder return (in shares) |
1,000,000
|
|
| Dividend rights accrued |
$ 0.7
|
|
| Unamortized stock based compensation expense |
$ 16.2
|
|
| Performance Shares | Minimum |
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
| Multiplier for shares granted |
0.00%
|
|
| Performance Shares | Maximum |
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
| Multiplier for shares granted |
250.00%
|
|