COMPREHENSIVE INCOME (LOSS) - Components (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
COMPREHENSIVE INCOME (LOSS)
Unrealized holding gains (losses) on available-for-sale debt securities	$ 11,512	$ (69,828)	$ (8,669)
Unrealized holding losses on available-for-sale debt securities, Income Tax Effect	(2,418)	14,665	1,821
Unrealized holding gains (losses) on available-for-sale debt securities, Net of Tax Amount	9,094	(55,163)	(6,848)
Reclassification adjustment for gains realized in income	3,036	(20)	(24)
Reclassification adjustment for gains realized in income, Income Tax Effect	(638)	4	5
Reclassification adjustment for gains realized in income. Net of Tax Amount	2,398	(16)	(19)
Other comprehensive loss from available-for-sale debt securities, Before-Tax Amount	14,548	(69,848)	(8,693)
Other comprehensive loss on available-for-sale debt securities, Income tax effect	(3,056)	14,669	1,826
Other comprehensive loss from available-for-sale debt securities, Net-of-Tax Amount	11,492	(55,179)	(6,867)
Changes from plan amendments and actuarial gains and losses, Before-Tax Amount	(9)	389	140
Changes from plan amendments and actuarial gains and losses, Income Tax Effect	2	(81)	(29)
Changes from plan amendments and actuarial gains and losses, Net-of-Tax Amount	(7)	308	111
Amortization of prior service cost and net actuarial loss included in net periodic benefit cost, Before-Tax Amount	(56)	(42)	(17)
Amortization of prior service cost and net actuarial loss included in net periodic benefit cost, Income Tax Effect	12	9	4
Amortization of prior service cost and net actuarial loss included in net periodic benefit cost, Net-of-Tax Amount	(44)	(33)	(13)
Other comprehensive (loss) income on pension and postretirement obligations	(65)	347	123
Other comprehensive income (loss) on unfunded retirement obligations, Income Tax Effect	14	(72)	(25)
Other comprehensive income (loss) on unfunded retirement obligations, Net-of-Tax Amount	(51)	275	98
Other comprehensive income (loss) before income tax	14,483	(69,501)	(8,570)
Total other comprehensive loss, Income Tax Effect	(3,042)	14,597	1,801
Total other comprehensive loss, Net-of-Tax Amount	$ 11,441	$ (54,904)	$ (6,769)