INVESTMENT SECURITIES - Summary of Maturities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Available for sale, Amortized Cost
Amortized Cost	$ 400,718	$ 231,791
Available for sale, Fair Value
Fair Value	410,624	235,821
Total debt securities
Available for sale, Amortized Cost
Within one year	0
After one year, but within five years	9,254
After five years, but within ten years	36,097
After ten years	336,966
Amortized Cost	382,317	219,544
Available for sale, Fair Value
Within one year	0
After one year, but within five years	9,629
After five years, but within ten years	36,863
After ten years	345,656
Fair Value	$ 392,148	$ 223,400

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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