Equity Compensation (Fair Value) (Details) - Stock options - USD ($) $ in Thousands |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2017 |
Jun. 30, 2016 |
Jun. 30, 2017 |
Jun. 30, 2016 |
|
| Stock options | ||||
| Total fair value for the awards vested during the period | $ 1,100 | $ 2,200 | ||
| Stock options granted (in shares) | 0 | 0 | ||
| Intrinsic-value | ||||
| Options Exercised | $ 6,734 | $ 585 | ||
| Options Exercisable | $ 19,345 | $ 4,553 | 19,345 | 4,553 |
| Options Vested and Expected to Vest | $ 21,817 | $ 4,574 | $ 21,817 | $ 4,574 |
| Assumptions used to estimate fair value of stock options | ||||
| Expected volatility (as a percent) | 62.00% | 62.00% | ||
| Expected dividends (as a percent) | 0.00% | 0.00% | ||
| Expected term | 6 years 1 month 6 days | 6 years 1 month 6 days | ||
| Risk-free rate (as a percent) | 1.10% | 1.10% | ||