Equity Compensation (Fair Value) (Details) - USD ($)
$ in Thousands |
12 Months Ended |
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
| Stock options |
|
|
|
| Total fair value for the awards vested during the period |
$ 5,400
|
|
|
| Stock options |
|
|
|
| Stock options |
|
|
|
| Stock options granted (in shares) |
50,000
|
238,516
|
1,592,268
|
| Intrinsic-value |
|
|
|
| Options Exercised |
$ 3,312
|
$ 1,432
|
$ 22,668
|
| Options Exercisable |
6,089
|
3,496
|
22,718
|
| Options Vested and Expected to Vest |
$ 6,280
|
$ 3,499
|
$ 27,663
|
| Assumptions used to estimate fair value of stock options |
|
|
|
| Expected volatility, minimum (as a percent) |
|
51.00%
|
49.00%
|
| Expected volatility, maximum (as a percent) |
|
55.00%
|
60.00%
|
| Expected volatility (as a percent) |
62.00%
|
|
|
| Expected dividends (as a percent) |
0.00%
|
0.00%
|
0.00%
|
| Expected term |
6 years 1 month 6 days
|
|
|
| Risk-free rate (as a percent) |
1.10%
|
|
|
| Risk-free rate, minimum (as a percent) |
|
1.30%
|
0.30%
|
| Risk-free rate, maximum (as a percent) |
|
1.80%
|
2.00%
|
| Stock options | Minimum |
|
|
|
| Assumptions used to estimate fair value of stock options |
|
|
|
| Expected term |
|
5 years 3 months 18 days
|
1 year
|
| Stock options | Maximum |
|
|
|
| Assumptions used to estimate fair value of stock options |
|
|
|
| Expected term |
|
6 years 1 month 6 days
|
6 years 1 month 6 days
|