SECURITIES - Schedule of Available For Sale Securities By Maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Maturities of Available-for-sale Debt Securities [Abstract]
Amortized Cost, Due in one year or less	$ 3,275
Amortized Cost, Due after one year through five years	10,703
Amortized Cost, Due after five years through ten years	37,520
Amortized Cost, Due after ten years	388,154
Amortized Cost, Available for sale securities with maturities amortized cost	439,652
Amortized Cost, Mortgage-backed securities	379,888
Amortized Cost, Total debt securities	819,540	$ 697,906
Fair Value, Due in one year or less	3,289
Fair Value, Due after one year through five years	10,961
Fair Value, Due after five years through ten years	39,209
Fair Value, Due after ten years	403,720
Fair Value, Available for sale securities with maturities fair value	457,179
Fair Value, Mortgage-backed securities	383,250
Fair Value, Total debt securities	$ 840,429	$ 734,845	$ 734,845