ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Changes in Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	$ 649,793	$ 568,887
Net current period other comprehensive (loss) income	(11,718)	21,553
Ending balance	647,009	602,006
Total
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(155,195)	(188,923)
Other comprehensive income (loss) before reclassification	(12,157)	21,167
Amounts reclassified from accumulated other comprehensive income (loss)	439	386
Net current period other comprehensive (loss) income	(11,718)	21,553
Ending balance	(166,913)	(167,370)
Unrealized Gains and Losses on Available- for-Sales Securities
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(154,460)	(188,154)
Other comprehensive income (loss) before reclassification	(12,157)	21,167
Amounts reclassified from accumulated other comprehensive income (loss)	428	375
Net current period other comprehensive (loss) income	(11,729)	21,542
Ending balance	(166,189)	(166,612)
Defined Benefit Pension Items
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(735)	(769)
Other comprehensive income (loss) before reclassification	0	0
Amounts reclassified from accumulated other comprehensive income (loss)	11	11
Net current period other comprehensive (loss) income	11	11
Ending balance	$ (724)	$ (758)