ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Accumulated Other Comprehensive income (loss) (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023
Accumulated other comprehensive income (loss), net of tax:
Balance	$ 1,250,596	$ 1,239,371	$ 1,226,225	$ 1,202,503	$ 1,191,253	$ 1,169,583	$ 1,226,225	$ 1,169,583
Net other comprehensive loss (income) during the period	9,810	2,686	6,113	(2,528)	(5,747)	(4,259)	18,609	(12,534)
Balance	1,263,929	1,250,596	1,239,371	1,204,344	1,202,503	1,191,253	1,263,929	1,204,344
AOCI Attributable to Parent [Member]
Accumulated other comprehensive income (loss), net of tax:
Balance	(82,780)	(85,466)	(91,579)	(104,385)	(98,638)	(94,379)	(91,579)	(94,379)
Other comprehensive income (loss) before reclassifications							12,433	(14,615)
Amounts reclassified from accumulated other comprehensive income (loss)							6,176	2,081
Net other comprehensive loss (income) during the period	9,810	2,686	6,113	(2,528)	(5,747)	(4,259)	18,609	(12,534)
Balance	(72,970)	$ (82,780)	(85,466)	(106,913)	$ (104,385)	(98,638)	(72,970)	(106,913)
Securities
Accumulated other comprehensive income (loss), net of tax:
Balance			(90,242)			(100,870)	(90,242)	(100,870)
Other comprehensive income (loss) before reclassifications							21,940	(15,338)
Amounts reclassified from accumulated other comprehensive income (loss)							1,569	2,666
Net other comprehensive loss (income) during the period							23,509	(12,672)
Balance	(66,733)			(113,542)			(66,733)	(113,542)
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Accumulated other comprehensive income (loss), net of tax:
Balance			(6,430)			(5,266)	(6,430)	(5,266)
Other comprehensive income (loss) before reclassifications							1,057	952
Amounts reclassified from accumulated other comprehensive income (loss)							(649)	(781)
Net other comprehensive loss (income) during the period							408	171
Balance	(6,022)			(5,095)			(6,022)	(5,095)
Derivatives
Accumulated other comprehensive income (loss), net of tax:
Balance			$ 5,093			$ 11,757	5,093	11,757
Other comprehensive income (loss) before reclassifications							(10,564)	(229)
Amounts reclassified from accumulated other comprehensive income (loss)							5,256	196
Net other comprehensive loss (income) during the period							(5,308)	(33)
Balance	$ (215)			$ 11,724			$ (215)	$ 11,724