Debt - 6.00% Senior Convertible Notes due 2020 (Details) - USD ($) $ in Millions |
Jun. 23, 2015 |
Jun. 17, 2015 |
Jun. 30, 2018 |
Dec. 31, 2017 |
|---|---|---|---|---|
| 6.00% Senior Convertible Notes Due 2020 | ||||
| Debt | ||||
| Stated interest rate (percent) | 6.00% | 6.00% | ||
| 7.50% Exchange Notes and 7.50% Notes | ||||
| Debt | ||||
| Stated interest rate (percent) | 7.50% | |||
| 7.50% Senior Exchange Convertible Notes | ||||
| Debt | ||||
| Stated interest rate (percent) | 7.50% | |||
| TPG Aviator, L.P. | ||||
| Debt | ||||
| Ownership percentage (percent) | 43.80% | |||
| Senior Notes | 6.00% Senior Convertible Notes Due 2020 | ||||
| Debt | ||||
| Stated interest rate (percent) | 6.00% | |||
| Aggregate principal amount | $ 80.0 | |||
| Senior Notes | 7.50% Exchange Notes and 7.50% Notes | ||||
| Debt | ||||
| Cash paid for interest | $ 1.5 | |||
| Senior Notes | TPG Aviator, L.P. | 6.00% Senior Convertible Notes Due 2020 | ||||
| Debt | ||||
| Aggregate principal amount | $ 20.0 | |||
| Proceeds from notes | $ 20.0 |