ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Accumulated Other Comprehensive (loss) income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Accumulated other comprehensive (loss) income, net of tax:
Balance	$ 1,169,583	$ 1,192,620	$ 701,096
Total other comprehensive income (loss), net of tax	2,800	(88,198)	(257)
Balance	1,226,225	1,169,583	1,192,620
Accumulated Other Comprehensive Loss, Net of Deferred Taxes
Accumulated other comprehensive (loss) income, net of tax:
Balance	(94,379)	(6,181)	(5,924)
Other comprehensive income (loss) before reclassifications	(702)	(86,564)
Amounts reclassified from accumulated other comprehensive income (loss)	3,502	(1,634)
Total other comprehensive income (loss), net of tax	2,800	(88,198)	(257)
Balance	(91,579)	(94,379)	(6,181)
Securities
Accumulated other comprehensive (loss) income, net of tax:
Balance	(100,870)	(7,864)
Other comprehensive income (loss) before reclassifications	7,498	(95,030)
Amounts reclassified from accumulated other comprehensive income (loss)	3,130	2,024
Total other comprehensive income (loss), net of tax	10,628	(93,006)
Balance	(90,242)	(100,870)	(7,864)
Defined Benefit Plans
Accumulated other comprehensive (loss) income, net of tax:
Balance	(5,266)	(1,306)
Other comprehensive income (loss) before reclassifications	(109)	(1,413)
Amounts reclassified from accumulated other comprehensive income (loss)	(1,055)	(2,547)
Total other comprehensive income (loss), net of tax	(1,164)	(3,960)
Balance	(6,430)	(5,266)	(1,306)
Accumulated Other Comprehensive Loss, Derivatives
Accumulated other comprehensive (loss) income, net of tax:
Balance	11,757	2,989
Other comprehensive income (loss) before reclassifications	(8,091)	9,879
Amounts reclassified from accumulated other comprehensive income (loss)	1,427	(1,111)
Total other comprehensive income (loss), net of tax	(6,664)	8,768
Balance	$ 5,093	$ 11,757	$ 2,989