ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance	$ 1,140,522	$ 1,155,287	$ 1,192,620	$ 1,204,276	$ 1,172,824	$ 701,096	$ 1,192,620	$ 701,096
Total other comprehensive (loss) income, net of tax	(23,086)	(20,570)	(43,199)	(5,618)	4,045	6,455	(86,855)	4,882
Balance	1,140,791	1,140,522	1,155,287	1,201,117	1,204,276	1,172,824	1,140,791	1,201,117
Accumulated Other Comprehensive (Loss) Income
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance	(69,950)	(49,380)	(6,181)	4,576	531	(5,924)	(6,181)	(5,924)
Other comprehensive (loss) income before reclassifications							(84,542)	6,178
Amounts reclassified from accumulated other comprehensive loss							(2,313)	(1,296)
Total other comprehensive (loss) income, net of tax	(23,086)	(20,570)	(43,199)	(5,618)	4,045	6,455	(86,855)	4,882
Balance	(93,036)	$ (69,950)	(49,380)	(1,042)	$ 4,576	531	(93,036)	(1,042)
Securities
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance			(7,864)			12,694	(7,864)	12,694
Other comprehensive (loss) income before reclassifications							(96,565)	(10,378)
Amounts reclassified from accumulated other comprehensive loss								(826)
Total other comprehensive (loss) income, net of tax							(96,565)	(11,204)
Balance	(104,429)			1,490			(104,429)	1,490
Defined Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance			(1,306)			(6,086)	(1,306)	(6,086)
Other comprehensive (loss) income before reclassifications							2,051	2,706
Amounts reclassified from accumulated other comprehensive loss							(1,923)	(1,082)
Total other comprehensive (loss) income, net of tax							128	1,624
Balance	(1,178)			(4,462)			(1,178)	(4,462)
Derivatives
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance			$ 2,989			$ (12,532)	2,989	(12,532)
Other comprehensive (loss) income before reclassifications							9,972	13,850
Amounts reclassified from accumulated other comprehensive loss							(390)	612
Total other comprehensive (loss) income, net of tax							9,582	14,462
Balance	$ 12,571			$ 1,930			$ 12,571	$ 1,930