Securities - Amortized Cost and Fair Value by Maturity Date (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Amortized cost
Within one year	$ 1,127
After one to five years	5,550
After five to ten years	119,724
After ten years	638,348
Total available-for-sale securities	764,749	$ 716,952
Estimated fair value
Within one year	1,131
After one to five years	5,594
After five to ten years	116,949
After ten years	532,853
Total	$ 656,527	745,969
Weighted average yield
Within one year	3.37%
After one to five years	4.09%
After five to ten years	3.29%
After ten years	2.53%
Total	2.66%
Mortgage-backed - GSE residential
Amortized cost
After one to five years	$ 24
After five to ten years	105
After ten years	178,158
Total available-for-sale securities	178,287	161,675
Estimated fair value
After one to five years	23
After five to ten years	101
After ten years	150,402
Total	$ 150,526	161,710
Weighted average yield
After one to five years	4.78%
After five to ten years	4.01%
After ten years	2.06%
Total	2.06%
Collateralized mortgage obligations - GSE residential
Amortized cost
After five to ten years	$ 2,365
After ten years	10,124
Total available-for-sale securities	12,489	18,130
Estimated fair value
After five to ten years	2,241
After ten years	9,496
Total	$ 11,737	18,431
Weighted average yield
After five to ten years	2.77%
After ten years	2.27%
Total	2.37%
State and political subdivisions
Amortized cost
Within one year	$ 1,127
After one to five years	5,028
After five to ten years	112,642
After ten years	450,066
Total available-for-sale securities	568,863	532,906
Estimated fair value
Within one year	1,131
After one to five years	5,070
After five to ten years	110,310
After ten years	372,955
Total	$ 489,466	561,468
Weighted average yield
Within one year	3.37%
After one to five years	3.88%
After five to ten years	3.26%
After ten years	2.73%
Total	2.85%
Corporate bonds
Amortized cost
After one to five years	$ 498
After five to ten years	4,612
Total available-for-sale securities	5,110	4,241
Estimated fair value
After one to five years	501
After five to ten years	4,297
Total	$ 4,798	$ 4,360
Weighted average yield
After one to five years	6.22%
After five to ten years	4.31%
Total	4.49%