Securities - Amortized Cost and Estimated Fair Value of Investment Securities by Contractual Maturity (Details) $ in Thousands	Sep. 30, 2021 USD ($)
Amortized Cost
Less than one year	$ 90,596
Due after one year through five years	154,228
Due after five years through ten years	222,930
Due after ten years	178,695
Total amortized cost	646,449
Estimated Fair Value
Less than one year	91,346
Due after one year through five years	157,403
Due after five years through ten years	222,072
Due after ten years	185,126
Total estimated fair value	$ 655,947