Securities (Details 3) - USD ($) $ in Thousands |
Jun. 30, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Available-for-sale securities, Amortized Cost | ||
| Total | $ 1,387,108 | $ 1,389,255 |
| Available-for-sale securities, Fair value | ||
| Total | 1,411,436 | 1,384,750 |
| Total debt securities [Member] | ||
| Available-for-sale securities, Amortized Cost | ||
| Due in one year or less | 27,577 | 53,936 |
| Due after one year through five years | 346,074 | 351,462 |
| Due after five years through ten years | 223,789 | 219,161 |
| Due after ten years | 12,195 | 13,098 |
| Total | 609,635 | 637,657 |
| Available-for-sale securities, Fair value | ||
| Due in one year or less | 27,854 | 54,735 |
| Due after one year through five years | 355,429 | 353,736 |
| Due after five years through ten years | 231,552 | 218,561 |
| Due after ten years | 11,983 | 12,749 |
| Total | 626,818 | 639,781 |
| Mortgage-backed securities [Member] | ||
| Available-for-sale securities, Amortized Cost | ||
| Total | 777,473 | 751,598 |
| Available-for-sale securities, Fair value | ||
| Total | $ 784,618 | $ 744,969 |