Securities - Amortized Cost and Fair Value by Maturity Date (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Amortized cost
Within one year	$ 796
After one to five years	5,269
After five to ten years	105,566
After ten years	652,943
Total available-for-sale securities	764,574	$ 716,952
Estimated fair value
Within one year	805
After one to five years	5,419
After five to ten years	106,084
After ten years	583,339
Total	$ 695,647	745,969
Weighted average yield
Within one year	3.44%
After one to five years	4.15%
After five to ten years	3.34%
After ten years	2.51%
Total	2.64%
Mortgage-backed - GSE residential
Amortized cost
After one to five years	$ 24
After five to ten years	117
After ten years	178,978
Total available-for-sale securities	179,119	161,675
Estimated fair value
After one to five years	24
After five to ten years	117
After ten years	160,628
Total	$ 160,769	161,710
Weighted average yield
After one to five years	4.71%
After five to ten years	4.03%
After ten years	2.00%
Total	2.00%
Collateralized mortgage obligations - GSE residential
Amortized cost
After five to ten years	$ 2,386
After ten years	11,225
Total available-for-sale securities	13,611	18,130
Estimated fair value
After five to ten years	2,338
After ten years	10,873
Total	$ 13,211	18,431
Weighted average yield
After five to ten years	2.77%
After ten years	2.19%
Total	2.29%
State and political subdivisions
Amortized cost
Within one year	$ 796
After one to five years	4,746
After five to ten years	98,444
After ten years	462,740
Total available-for-sale securities	566,726	532,906
Estimated fair value
Within one year	805
After one to five years	4,871
After five to ten years	99,175
After ten years	411,838
Total	$ 516,689	561,468
Weighted average yield
Within one year	3.44%
After one to five years	3.89%
After five to ten years	3.31%
After ten years	2.72%
Total	2.83%
Corporate bonds
Amortized cost
After one to five years	$ 499
After five to ten years	4,619
Total available-for-sale securities	5,118	4,241
Estimated fair value
After one to five years	524
After five to ten years	4,454
Total	$ 4,978	$ 4,360
Weighted average yield
After one to five years	6.63%
After five to ten years	4.29%
Total	4.52%