Equity Compensation - Unrecognized Compensation Expense (Details) - USD ($) $ in Thousands |
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|---|---|---|---|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Unrecognized compensation expense | $ 12,049 | $ 10,535 | $ 7,061 |
| Non-qualified stock options | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Unrecognized compensation expense | 175 | 1,059 | 2,600 |
| Restricted stock and restricted stock units | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Unrecognized compensation expense | 8,740 | 9,476 | 4,461 |
| Performance shares and performance share units | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Unrecognized compensation expense | $ 3,134 | $ 0 | $ 0 |