Equity Compensation (Fair Value) (Details) - Stock options - USD ($) $ in Thousands |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2017 |
Sep. 30, 2016 |
Sep. 30, 2017 |
Sep. 30, 2016 |
|
| Stock options | ||||
| Total fair value for the awards vested during the period | $ 800 | $ 3,000 | ||
| Stock options granted (in shares) | 0 | 0 | ||
| Intrinsic-value | ||||
| Options Exercised | $ 8,927 | $ 2,978 | ||
| Options Exercisable | $ 39,360 | $ 10,491 | 39,360 | 10,491 |
| Options Vested and Expected to Vest | $ 45,152 | $ 11,065 | $ 45,152 | $ 11,065 |
| 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% | ||