Securities - Securities with Unrealized Losses (Details) - USD ($)
$ in Thousands |
Jun. 30, 2019 |
Dec. 31, 2018 |
| Available-for-sale securities |
|
|
| Fair value, less than 12 months |
$ 50,394
|
$ 111,648
|
| Unrealized losses, less than 12 months |
237
|
886
|
| Fair value, 12 months or longer |
639,407
|
1,109,535
|
| Unrealized losses, 12 months or longer |
7,535
|
31,256
|
| Fair Value |
689,801
|
1,221,183
|
| Unrealized Losses |
7,772
|
32,142
|
| Held-to-maturity debt securities |
|
|
| Fair value, less than 12 months |
1,290
|
13,107
|
| Unrealized losses, less than 12 months |
1
|
33
|
| Fair value, 12 months or longer |
0
|
125,128
|
| Unrealized losses, 12 months or longer |
0
|
1,189
|
| Fair Value |
1,290
|
138,235
|
| Unrealized Losses |
1
|
1,222
|
| U.S. Treasuries |
|
|
| Available-for-sale securities |
|
|
| Fair value, less than 12 months |
278
|
|
| Unrealized losses, less than 12 months |
2
|
|
| Fair value, 12 months or longer |
0
|
|
| Unrealized losses, 12 months or longer |
0
|
|
| Fair Value |
278
|
|
| Unrealized Losses |
2
|
|
| Obligations of U.S. Government sponsored entities |
|
|
| Available-for-sale securities |
|
|
| Fair value, less than 12 months |
0
|
21,660
|
| Unrealized losses, less than 12 months |
0
|
183
|
| Fair value, 12 months or longer |
149,248
|
449,141
|
| Unrealized losses, 12 months or longer |
260
|
7,370
|
| Fair Value |
149,248
|
470,801
|
| Unrealized Losses |
260
|
7,553
|
| Held-to-maturity debt securities |
|
|
| Fair value, less than 12 months |
|
4,980
|
| Unrealized losses, less than 12 months |
|
9
|
| Fair value, 12 months or longer |
|
125,128
|
| Unrealized losses, 12 months or longer |
|
1,189
|
| Fair Value |
|
130,108
|
| Unrealized Losses |
|
1,198
|
| Obligations of U.S. states and political subdivisions |
|
|
| Available-for-sale securities |
|
|
| Fair value, less than 12 months |
5,817
|
11,971
|
| Unrealized losses, less than 12 months |
8
|
19
|
| Fair value, 12 months or longer |
5,021
|
49,756
|
| Unrealized losses, 12 months or longer |
27
|
914
|
| Fair Value |
10,838
|
61,727
|
| Unrealized Losses |
35
|
933
|
| Held-to-maturity debt securities |
|
|
| Fair value, less than 12 months |
1,290
|
8,127
|
| Unrealized losses, less than 12 months |
1
|
24
|
| Fair value, 12 months or longer |
0
|
0
|
| Unrealized losses, 12 months or longer |
0
|
0
|
| Fair Value |
1,290
|
8,127
|
| Unrealized Losses |
1
|
24
|
| U.S. Government agencies |
|
|
| Available-for-sale securities |
|
|
| Fair value, less than 12 months |
23,908
|
16,854
|
| Unrealized losses, less than 12 months |
184
|
22
|
| Fair value, 12 months or longer |
73,414
|
96,247
|
| Unrealized losses, 12 months or longer |
1,349
|
3,710
|
| Fair Value |
97,322
|
113,101
|
| Unrealized Losses |
1,533
|
3,732
|
| U.S. Government sponsored entities |
|
|
| Available-for-sale securities |
|
|
| Fair value, less than 12 months |
20,391
|
61,163
|
| Unrealized losses, less than 12 months |
43
|
662
|
| Fair value, 12 months or longer |
409,292
|
512,216
|
| Unrealized losses, 12 months or longer |
5,831
|
18,937
|
| Fair Value |
429,683
|
573,379
|
| Unrealized Losses |
5,874
|
19,599
|
| U.S. corporate debt securities |
|
|
| Available-for-sale securities |
|
|
| Fair value, less than 12 months |
0
|
0
|
| Unrealized losses, less than 12 months |
0
|
0
|
| Fair value, 12 months or longer |
2,432
|
2,175
|
| Unrealized losses, 12 months or longer |
68
|
325
|
| Fair Value |
2,432
|
2,175
|
| Unrealized Losses |
$ 68
|
$ 325
|