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OTHER COMPREHENSIVE INCOME (LOSS) Components of Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Jun. 30, 2022	Dec. 31, 2021	Jun. 30, 2021	Dec. 31, 2020
AFS Debt Securities:
Unrealized holding gains, pre-tax amount	$ (28,432)	$ (6,546)	$ (173,421)	$ (25,926)
Unrealized holdings gains, tax (expense) benefit	6,113	1,407	37,286	5,574
Unrealized holdings gains, after-tax amount	(22,319)	(5,139)	(136,135)	(20,352)
Less: reclassification adjustment for amortization of securities transferred from AFS to HTM, pre-tax amount	2,436	0	3,780	0
Less: reclassification adjustment for amortization of securities transferred from AFS to HTM, tax (expense) benefit	(524)	0	(813)	0
Less: reclassification adjustment for amortization of securities transferred from AFS to HTM, after-tax amount	1,912	0	2,967	0
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax			(9)	0
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax			2	0
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax			(7)	0
Net unrealized gains, pre-tax amount	(30,868)	(6,546)	(177,192)	(25,926)
Net unrealized gains, tax (expense) benefit	6,637	1,407	38,097	5,574
Net unrealized gains, after-tax amount	(24,231)	(5,139)	(139,095)	(20,352)
Cash Flow Hedges:
Net decrease in fair value, pre-tax amount	3,381	466	10,604	3,655
Net decrease in fair value, tax (expense) benefit	(727)	(100)	(2,280)	(785)
Net decrease in fair value, after-tax amount	2,654	366	8,324	2,870
Net decrease in fair value, pre-tax amount	3,261	595	10,604	4,162
Net decrease in fair value, tax (expense) benefit	(701)	(128)	(2,280)	(895)
Net decrease in fair value, after-tax amount	2,560	467	8,324	3,267
Postretirement Plans:
Net gain on postretirement plans, pre-tax amount	230	217	693	652
Net gain on postretirement plans, tax (expense) benefit	(49)	(46)	(149)	(140)
Net gain on postretirement plans, net of tax	181	171	544	512
Other comprehensive income, pre-tax amount	(27,377)	(5,734)	(165,895)	(21,112)
Other comprehensive income, tax (expense) benefit	5,887	1,233	35,668	4,539
Other comprehensive loss	(21,490)	(4,501)	(130,227)	(16,573)
Allowance for credit losses	36,542	32,272	36,542	32,272	$ 34,244	$ 33,256	$ 32,060	$ 37,865
Commercial real estate - non-owner-occupied, hospitality-related
Postretirement Plans:
Allowance for credit losses	0		0			$ 5,000
Interest Expense, Borrowings
Cash Flow Hedges:
Less: effective portion reclassified into interest expense, pre-tax amount	241	(539)	(498)	(1,712)
Less: effective portion reclassified into interest expense, tax (expense) benefit	(52)	116	107	368
Less: effective portion reclassified into interest expense, after-tax amount	189	(423)	(391)	(1,344)
Interest Income, Interest and Fees on Loans
Cash Flow Hedges:
Less: effective portion reclassified into interest expense, pre-tax amount	(121)	410	498	1,205
Less: effective portion reclassified into interest expense, tax (expense) benefit	26	(88)	(107)	(258)
Less: effective portion reclassified into interest expense, after-tax amount	$ (95)	$ 322	$ 391	$ 947

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