Stock-Based Compensation - Compensation Expense (Details) - USD ($) $ in Thousands |
3 Months Ended | |
|---|---|---|
Mar. 31, 2018 |
Mar. 31, 2017 |
|
| Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] | ||
| Total equity based compensation expense | $ 4,333 | $ 2,610 |
| Restricted stock awards | ||
| Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] | ||
| Total equity based compensation expense | 1,775 | 856 |
| Stock option awards | ||
| Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] | ||
| Total equity based compensation expense | 2,206 | 1,754 |
| Performance stock units | ||
| Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] | ||
| Total equity based compensation expense | $ 352 | $ 0 |