Securities - Amortized Cost and Fair Value by Maturity Date (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Amortized cost
Within one year	$ 1,068
After one to five years	6,058
After five to ten years	104,198
After ten years	710,858
Total available-for-sale securities	822,182	$ 769,641
Estimated fair value
Within one year	1,076
After one to five years	6,119
After five to ten years	101,767
After ten years	634,938
Total	$ 743,900	686,901
Weighted average yield
Within one year	3.55%
After one to five years	4.32%
After five to ten years	3.33%
After ten years	2.96%
Total	3.01%
Mortgage-backed - GSE residential
Amortized cost
After one to five years	$ 14
After five to ten years	1,053
After ten years	296,874
Total available-for-sale securities	297,941	197,243
Estimated fair value
After one to five years	13
After five to ten years	965
After ten years	271,955
Total	$ 272,933	172,309
Weighted average yield
After one to five years	4.82%
After five to ten years	2.40%
After ten years	3.29%
Total	3.29%
Collateralized mortgage obligations - GSE residential
Amortized cost
After five to ten years	$ 2,296
After ten years	7,960
Total available-for-sale securities	10,256	11,629
Estimated fair value
After five to ten years	2,165
After ten years	7,351
Total	$ 9,516	10,886
Weighted average yield
After five to ten years	2.77%
After ten years	2.34%
Total	2.43%
State and political subdivisions
Amortized cost
Within one year	$ 1,068
After one to five years	5,900
After five to ten years	91,244
After ten years	406,024
Total available-for-sale securities	504,236	551,007
Estimated fair value
Within one year	1,076
After one to five years	5,966
After five to ten years	90,275
After ten years	355,632
Total	$ 452,949	494,496
Weighted average yield
Within one year	3.55%
After one to five years	4.32%
After five to ten years	3.10%
After ten years	2.72%
Total	2.81%
Corporate bonds
Amortized cost
After one to five years	$ 144
After five to ten years	9,605
Total available-for-sale securities	9,749	9,762
Estimated fair value
After one to five years	140
After five to ten years	8,362
Total	$ 8,502	$ 9,210
Weighted average yield
After one to five years	4.29%
After five to ten years	5.70%
Total	5.68%