Share-Based Compensation - Stock Option Activity (Details) - $ / shares
shares in Thousands |
12 Months Ended |
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
| Shares |
|
|
|
| Options beginning balance (in shares) |
2,882
|
3,311
|
3,026
|
| Options granted (in shares) |
163
|
383
|
574
|
| Options exercised (in shares) |
(1,117)
|
(803)
|
(273)
|
| Options forfeited (in shares) |
0
|
0
|
(1)
|
| Options expired (in shares) |
0
|
(9)
|
(15)
|
| Options ending balance (in shares) |
1,928
|
2,882
|
3,311
|
| Weighted Average Grant Date Fair Value per Share |
|
|
|
| Options beginning balance (in dollars per share) |
$ 4.24
|
$ 3.95
|
$ 3.97
|
| Options granted (in dollars per share) |
8.85
|
6.32
|
3.89
|
| Options exercised (in dollars per share) |
3.88
|
4.06
|
3.93
|
| Options forfeited (in dollars per share) |
0
|
0
|
4.97
|
| Options expired (in dollars per share) |
0
|
4.05
|
4.76
|
| Options ending balance (in dollars per share) |
4.84
|
4.24
|
3.95
|
| Weighted Average Exercise Price |
|
|
|
| Options beginning balance (in dollars per share) |
11.42
|
10.41
|
10.27
|
| Options granted (in dollars per share) |
22.19
|
18.08
|
11.06
|
| Options exercised (in dollars per share) |
10.19
|
10.43
|
10.17
|
| Options forfeited (in dollars per share) |
0
|
0
|
12.32
|
| Options expired (in dollars per share) |
0
|
10.51
|
12.02
|
| Options beginning balance (in dollars per share) |
$ 13.04
|
$ 11.42
|
$ 10.41
|