INVESTMENT SECURITIES - Amortized Cost and Fair Value of Available for Sale Securities and Held to Maturity Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Amortized Cost
Due in one year or less	$ 2,402	$ 1,390
Due after one through five years	24,675	24,899
Due after five through ten years	160,390	127,948
Due after ten years	1,112,693	1,151,260
Total debt securities with a single maturity date	1,300,160	1,305,497
Total investment securities	1,884,215	1,846,840
Fair Value
Due in one year or less	2,383	1,382
Due after one through five years	22,920	23,372
Due after five through ten years	144,580	120,385
Due after ten years	958,356	1,027,158
Total debt securities with a single maturity date	1,128,239	1,172,297
Total investment securities	1,618,893	1,627,112
Amortized Cost
Due in one year or less	13,380	3,041
Due after one through five years	113,750	118,592
Due after five through ten years	139,308	135,805
Due after ten years	1,191,857	1,217,265
Total debt securities with a single maturity date	1,458,295	1,474,703
Total investment securities	2,134,440	2,184,497
Fair Value
Due in one year or less	13,249	3,043
Due after one through five years	106,226	111,723
Due after five through ten years	125,618	126,461
Due after ten years	963,585	1,018,801
Total debt securities with a single maturity date	1,208,678	1,260,028
Total investment securities	1,779,216	1,870,374
U.S. Government-sponsored mortgage-backed securities
Amortized Cost
U.S. Government-sponsored mortgage-backed securities	584,055	541,343
Fair Value
U.S. Government-sponsored mortgage-backed securities	490,654	454,815
Total investment securities	490,654	454,815
Amortized Cost
U.S. Government-sponsored mortgage-backed securities	676,145	709,794
Total investment securities	676,145	709,794
Fair Value
U.S. Government-sponsored mortgage-backed securities	570,538	610,346
Total investment securities	$ 570,538	$ 610,346