Incentive Award Plan - Narrative (Details) - USD ($)
$ in Millions |
|
3 Months Ended |
9 Months Ended |
|
May 11, 2016 |
Sep. 30, 2016 |
Sep. 30, 2015 |
Sep. 30, 2016 |
Sep. 30, 2015 |
Dec. 31, 2015 |
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
|
|
|
|
| Increase in number of shares reserved for issuance (in shares) |
5,500,000
|
|
|
|
|
|
| Number of shares available under plan (in shares) |
|
5,700,000
|
|
5,700,000
|
|
|
| Performance award plan, shares released due to terminations |
|
|
|
200,000
|
|
|
| Unamortized stock-based compensation expense |
|
$ 16.7
|
|
$ 16.7
|
|
|
| General and Administrative Expense |
|
|
|
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
|
|
|
|
| Stock-based compensation expense |
|
$ 3.4
|
$ 3.5
|
7.2
|
$ 10.8
|
|
| Non-vested Shares of Restricted Stock |
|
|
|
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
|
|
|
|
| Deferred compensation expense |
|
|
|
$ 11.7
|
|
|
| Outstanding unvested shares (in shares) |
|
1,000,000
|
|
1,000,000
|
|
|
| Unamortized stock-based compensation expense |
|
$ 11.2
|
|
$ 11.2
|
|
|
| Non-vested Shares of Restricted Stock | Executives Officers And Employees |
|
|
|
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
|
|
|
|
| Grants in period (in shares) |
|
|
|
900,000
|
|
|
| Performance Shares |
|
|
|
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
|
|
|
|
| Approved initial target grant (in shares) |
|
|
|
300,000
|
|
|
| Performance shares forfeitures (in shares) |
|
|
|
100,000
|
|
|
| Minimum required service period |
|
|
|
3 years
|
|
|
| Stock-based compensation expense |
|
|
|
$ 4.1
|
|
|
| Dividend rights accrued |
|
$ 0.4
|
|
$ 0.4
|
|
$ 0.2
|
| Potential grants in period based on total shareholder return (in shares) |
|
800,000
|
|
800,000
|
|
|
| Unamortized stock-based compensation expense |
|
$ 5.5
|
|
$ 5.5
|
|
|
| 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%
|
|
|