Debt - 6.00% Senior Convertible Notes due 2020 (Details) - Senior Notes - USD ($) |
Jun. 23, 2015 |
Jun. 17, 2015 |
Dec. 31, 2016 |
Jul. 20, 2015 |
Dec. 31, 2014 |
Jul. 31, 2012 |
|---|---|---|---|---|---|---|
| 6.00% Senior Convertible Notes Due 2020 | ||||||
| Debt | ||||||
| Stated interest rate (percent) | 6.00% | 6.00% | ||||
| Aggregate principal amount | $ 80,000,000 | |||||
| Face amount of debt repurchased | 15,400,000 | |||||
| Proceeds from notes | 64,500,000 | |||||
| 7.50% Exchange Notes and 7.50% Notes | ||||||
| Debt | ||||||
| Cash paid for interest | 1,500,000 | |||||
| Face amount of debt repurchased | $ 30,700,000 | |||||
| 7.50% Senior Exchange Convertible Notes | ||||||
| Debt | ||||||
| Stated interest rate (percent) | 7.50% | 7.50% | 7.50% | 7.50% | ||
| Aggregate principal amount | $ 44,500,000 | |||||
| Face amount of debt repurchased | $ 20,500,000 | |||||
| TPG Aviator, L.P. | 6.00% Senior Convertible Notes Due 2020 | TPG Aviator, L.P. | ||||||
| Debt | ||||||
| Stated interest rate (percent) | 6.00% | |||||
| Aggregate principal amount | $ 20,000,000 | |||||
| Ownership interest (as a percent) | 43.50% | |||||
| Proceeds from notes | $ 20,000,000 |