OTHER COMPREHENSIVE INCOME (LOSS) Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	$ 464,874	$ 482,446	$ 451,278	$ 541,294
Other comprehensive income (loss) before reclassifications	(1,239)	(39,243)	1,419	(109,201)
Less: Amounts reclassified from AOCI	1,224	(190)	(2,602)	(464)
Other comprehensive (loss) income	(2,463)	(39,053)	4,021	(108,737)
Ending Balance	467,376	446,381	467,376	446,381
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(119,471)	(75,913)	(125,955)	(6,229)
Ending Balance	(121,934)	(114,966)	(121,934)	(114,966)
Net Unrealized Gains (Losses) on Debt Securities(1)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(122,445)	(73,984)	(131,539)	(1,173)
Other comprehensive income (loss) before reclassifications	(4,053)	(42,060)	1,045	(114,871)
Less: Amounts reclassified from AOCI	1,331	(7)	(2,665)	(7)
Other comprehensive (loss) income	(5,384)	(42,053)	3,710	(114,864)
Ending Balance	(127,829)	(116,037)	(127,829)	(116,037)
Net Unrealized (Losses) Gains on Cash Flow Hedges(1)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	3,286	1,166	5,891	(1,779)
Other comprehensive income (loss) before reclassifications	2,814	2,817	374	5,670
Less: Amounts reclassified from AOCI	(113)	(2)	52	(94)
Other comprehensive (loss) income	2,927	2,819	322	5,764
Ending Balance	6,213	3,985	6,213	3,985
Defined Benefit Postretirement Plans(1)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(312)	(3,095)	(307)	(3,277)
Other comprehensive income (loss) before reclassifications	0	0	0	0
Less: Amounts reclassified from AOCI	6	(181)	11	(363)
Other comprehensive (loss) income	(6)	181	(11)	363
Ending Balance	$ (318)	$ (2,914)	$ (318)	$ (2,914)