SECURITIES - Summary of Available For Sale and Held to Maturity Securities (Details) - USD ($)	Jun. 30, 2023	Dec. 31, 2022
Debt Securities, Available-for-Sale [Abstract]
Amortized Cost	$ 1,264,061,000	$ 1,400,783,000
Gross Unrealized Gain	44,000	224,000
Gross Unrealized Losses	(202,036,000)	(215,479,000)
Allowance for Credit Losses	0	0
Fair Value	1,062,069,000	1,185,528,000
U.S. Treasury securities
Debt Securities, Available-for-Sale [Abstract]
Amortized Cost	3,251,000	3,057,000
Gross Unrealized Gain	0	0
Gross Unrealized Losses	(19,000)	(23,000)
Allowance for Credit Losses	0	0
Fair Value	3,232,000	3,034,000
U.S. government sponsored agencies
Debt Securities, Available-for-Sale [Abstract]
Amortized Cost	151,029,000	156,184,000
Gross Unrealized Gain	0	0
Gross Unrealized Losses	(28,943,000)	(29,223,000)
Allowance for Credit Losses	0	0
Fair Value	122,086,000	126,961,000
Mortgage-backed securities: residential
Debt Securities, Available-for-Sale [Abstract]
Amortized Cost	545,616,000	578,175,000
Gross Unrealized Gain	34,000	67,000
Gross Unrealized Losses	(83,617,000)	(85,934,000)
Allowance for Credit Losses	0	0
Fair Value	462,033,000	492,308,000
State and municipal securities
Debt Securities, Available-for-Sale [Abstract]
Amortized Cost	564,165,000	663,367,000
Gross Unrealized Gain	10,000	157,000
Gross Unrealized Losses	(89,457,000)	(100,299,000)
Allowance for Credit Losses	0	0
Fair Value	$ 474,718,000	$ 563,225,000