Investment Securities - Amortized cost and estimated fair value (Details) $ in Thousands	Sep. 30, 2022 USD ($)
Carrying Value
Due within one year or less	$ 6,808
Due after one year through five years	40,702
Due after five years through ten years	69,679
Due after 10 years	209,221
Total investment securities	326,410
Estimated Fair Value
Due within one year or less	6,742
Due after one year through five years	37,102
Due after five years through ten years	58,557
Due after 10 years	170,905
Total investment securities	273,306
Amortized Cost
Due within one year or less	11
Due after one year through five years	21,421
Due after five years through ten years	89,695
Due after 10 years	756,016
Total investment securities available-for-sale	867,143
Fair Value
Due within one year or less	11
Due after one year through five years	19,957
Due after five years through ten years	81,580
Due after 10 years	627,562
Total investment securities available-for-sale	$ 729,110