INVESTMENT SECURITIES - Investments classified by contractual maturity date (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Available-for-Sale - Amortized Cost
After three through four years	$ 245
After four through five years	936
After five through fifteen years	6,365
After fifteen years	51,857
Securities not due on a single maturity date	479,754
Available-for-sale securities, Amortized Cost, Total	539,157	$ 553,214
Available-for-Sale - Fair Value
After three through four years	245
After four through five years	940
After five through fifteen years	6,135
After fifteen years	49,403
Securities not due on a single maturity date	420,188
Available-for-sale securities, Fair Value, Total	476,911	490,592
Held-to-Maturity - Amortized Carrying Value
After five through fifteen years	3,250
After fifteen years	2,958
Securities not due on a single maturity date	192,179
Amortized Carrying Value	198,387	202,495
Held-to-Maturity - Fair Value
After five through fifteen years	2,896
After fifteen years	2,633
Securities not due on a single maturity date	168,132
Total fair value of held-to-maturity	$ 173,661	$ 177,765