SECURITIES AND OTHER INVESTMENTS (Amortized Cost of HTM Securities by Security Type and Credit Rating) (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
HTM Securities, Amortized Cost	$ 828,928	$ 837,378
Moody's AAA/AA/A
HTM Securities, Amortized Cost	694,459	698,219
Moody's BBB/BB/B
HTM Securities, Amortized Cost	1,160	1,166
Moody's Not Rated - Agency
HTM Securities, Amortized Cost	67,305	68,039
Moody's Not Rated - Non-Agency
HTM Securities, Amortized Cost	66,004	69,954
Obligations of states and political subdivisions
HTM Securities, Amortized Cost	695,952	699,189
Obligations of states and political subdivisions | Moody's AAA/AA/A
HTM Securities, Amortized Cost	685,273	688,499
Obligations of states and political subdivisions | Moody's BBB/BB/B
HTM Securities, Amortized Cost	1,160	1,166
Obligations of states and political subdivisions | Moody's Not Rated - Agency
HTM Securities, Amortized Cost	0	0
Obligations of states and political subdivisions | Moody's Not Rated - Non-Agency
HTM Securities, Amortized Cost	9,519	9,524
Corporate and other bonds
HTM Securities, Amortized Cost	4,230	4,349
Corporate and other bonds | Moody's AAA/AA/A
HTM Securities, Amortized Cost	0	0
Corporate and other bonds | Moody's BBB/BB/B
HTM Securities, Amortized Cost	0	0
Corporate and other bonds | Moody's Not Rated - Agency
HTM Securities, Amortized Cost	0	0
Corporate and other bonds | Moody's Not Rated - Non-Agency
HTM Securities, Amortized Cost	4,230	4,349
Mortgage-backed securities
HTM Securities, Amortized Cost	128,746	133,840
Mortgage-backed securities | Moody's AAA/AA/A
HTM Securities, Amortized Cost	9,186	9,720
Mortgage-backed securities | Moody's BBB/BB/B
HTM Securities, Amortized Cost	0	0
Mortgage-backed securities | Moody's Not Rated - Agency
HTM Securities, Amortized Cost	67,305	68,039
Mortgage-backed securities | Moody's Not Rated - Non-Agency
HTM Securities, Amortized Cost	$ 52,255	$ 56,081