Share-Based Compensation - Restricted Stock Units Activity (Details) - Restricted Stock Units (RSUs) - $ / shares shares in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Shares | |||
| Non-vested restricted stock units, beginning balance (in shares) | 1,753 | 2,065 | 2,538 |
| Restricted stock units granted (in shares) | 470 | 701 | 988 |
| Restricted stock units vested (in shares) | (970) | (913) | (1,367) |
| Restricted stock units forfeited (in shares) | (51) | (100) | (94) |
| Non-vested restricted stock units, ending balance (in shares) | 1,202 | 1,753 | 2,065 |
| Weighted Average Grant Date Fair Value per Share | |||
| Non-vested restricted stock units, beginning balance (in dollars per share) | $ 12.06 | $ 8.15 | $ 6.01 |
| Restricted stock units granted (in dollars per share) | 24.42 | 17.22 | 11.22 |
| Restricted stock units vested (in dollars per share) | 9.71 | 7.42 | 6.67 |
| Restricted stock units forfeited (in dollars per share) | 15.06 | 9.89 | 8.96 |
| Non-vested restricted stock units, ending balance (in dollars per share) | $ 18.67 | $ 12.06 | $ 8.15 |