INVESTMENT SECURITIES, Contractual or Expected Maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Maturity in years [Abstract]
Due in one year or less	$ 15,608
Due after one year through five years	126,175
Due after five years through ten years	52,282
Due after ten years	24,021
Subtotal	218,086
MBS & CMO	396,165
Amortized cost	614,251	$ 424,981
Maturity in years [Abstract]
Due in one year or less	15,763
Due after one year through five years	126,715
Due after five years through ten years	52,037
Due after ten years	24,449
Subtotal	218,964
MBS & CMO	398,146
Estimated fair value	$ 617,110	$ 435,080