Investment Securities, Contractual and Expected Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Maturity in years [Abstract]
Due in one year or less	$ 16,281
Due after one year through five years	78,502
Due after five years through ten years	58,501
Due after ten years	21,145
Subtotal	174,429
MBS & CMO	250,552
Amortized cost	424,981	$ 340,706
Maturity in years [Abstract]
Due in one year or less	16,447
Due after one year through five years	80,214
Due after five years through ten years	59,251
Due after ten years	22,419
Subtotal	178,331
MBS & CMO	256,749
Estimated fair value	$ 435,080	$ 342,897