Securities - Available for Sale Securities Amortized Cost and Estimated Fair Value (Details) - USD ($) $ in Thousands |
Jun. 30, 2019 |
Dec. 31, 2018 |
|---|---|---|
| Amortized Cost | ||
| Amortized Cost | $ 1,190,869 | $ 1,363,902 |
| Fair Value | ||
| Total | 1,189,246 | 1,332,658 |
| Total available-for-sale securities | ||
| Amortized Cost | ||
| Due in one year or less | 100,288 | 78,160 |
| Due after one year through five years | 216,859 | 355,499 |
| Due after five years through ten years | 101,881 | 139,560 |
| Due after ten years | 12,003 | 9,201 |
| Amortized Cost | 431,031 | 582,420 |
| Fair Value | ||
| Due in one year or less | 100,208 | 77,930 |
| Due after one year through five years | 218,049 | 350,470 |
| Due after five years through ten years | 102,879 | 136,734 |
| Due after ten years | 12,019 | 8,668 |
| Total | 433,155 | 573,802 |
| Mortgage-backed securities | ||
| Amortized Cost | ||
| Amortized Cost | 759,838 | 781,482 |
| Fair Value | ||
| Total | $ 756,091 | $ 758,856 |