Securities - Amortized Cost and Fair Value by Maturity Date (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Amortized cost
Within one year	$ 519
After one to five years	6,036
After five to ten years	67,862
After ten years	785,792
Amortized Cost	860,209	$ 829,387
Estimated fair value
Within one year	527
After one to five years	5,908
After five to ten years	65,750
After ten years	714,418
Total	$ 786,603	766,653
Weighted average yield
Within one year	4.41%
After one to five years	3.74%
After five to ten years	3.21%
After ten years	3.47%
Total	3.46%
Federal agency obligations
Amortized cost
After ten years	$ 9,989
Amortized Cost	9,989	9,988
Estimated fair value
After ten years	10,031
Total	$ 10,031	10,072
Weighted average yield
After ten years	6.38%
Total	6.38%
Mortgage-backed - GSE residential
Amortized cost
After five to ten years	$ 852
After ten years	251,142
Amortized Cost	251,994	233,203
Estimated fair value
After five to ten years	778
After ten years	227,882
Total	$ 228,660	212,462
Weighted average yield
After five to ten years	2.24%
After ten years	3.39%
Total	3.39%
Collateralized mortgage obligations - GSE residential
Amortized cost
After one to five years	$ 2,190
After ten years	68,915
Amortized Cost	71,105	50,125
Estimated fair value
After one to five years	2,093
After ten years	68,175
Total	$ 70,268	49,944
Weighted average yield
After one to five years	2.78%
After ten years	5.44%
Total	5.36%
State and political subdivisions
Amortized cost
Within one year	$ 519
After one to five years	3,597
After five to ten years	57,443
After ten years	332,607
Amortized Cost	394,166	396,349
Estimated fair value
Within one year	527
After one to five years	3,576
After five to ten years	56,560
After ten years	287,120
Total	$ 347,783	355,897
Weighted average yield
Within one year	4.41%
After one to five years	4.27%
After five to ten years	2.81%
After ten years	2.52%
Total	2.58%
Small Business Administration loan pools
Amortized cost
After one to five years	$ 10
After five to ten years	75
After ten years	123,139
Amortized Cost	123,224	125,017
Estimated fair value
After one to five years	10
After five to ten years	73
After ten years	121,210
Total	$ 121,293	124,778
Weighted average yield
After one to five years	4.96%
After five to ten years	4.07%
After ten years	4.86%
Total	4.86%
Corporate bonds
Amortized cost
After one to five years	$ 239
After five to ten years	9,492
Amortized Cost	9,731	9,740
Estimated fair value
After one to five years	229
After five to ten years	8,339
Total	$ 8,568	$ 8,532
Weighted average yield
After one to five years	4.59%
After five to ten years	5.71%
Total	5.69%