INVESTMENT SECURITIES - Investments Classified by Contractual Maturity Date (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Available-for-Sale - Amortized cost
After four through five years	$ 2,289
After five through fifteen years	14,524
After fifteen years	50,736
Securities not due on a single maturity date	488,697
Available-for-sale Securities, Amortized Cost Basis, Total	556,246
Available-for-Sale - Fair Value
After four through five years	2,297
After five through fifteen years	14,358
After fifteen years	48,709
Securities not due on a single maturity date	454,108
Available-for-sale Securities, Total	519,472	$ 501,032
Held-to-Maturity - Amortized Carrying Value
After five through fifteen years	2,576
After fifteen years	3,670
Securities not due on a single maturity date	209,108
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss, Total	215,354
Held-to-Maturity - Fair Value
After five through fifteen years	2,253
After fifteen years	3,284
Securities not due on a single maturity date	193,716
Held-to-maturity Fair Value, Total	$ 199,253