ACCUMULATED OTHER COMPREHENSIVE LOSS - Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Accumulated Other Comprehensive Loss
Beginning balance	$ 2,212,525	$ 2,145,565	$ 2,247,713	$ 2,034,770
Other comprehensive income before reclassifications			16,905	(71,775)
Amounts reclassified from accumulated other comprehensive loss			7,240	3,656
Period change	60,154	(89,306)	24,145	(68,119)
Ending balance	2,302,373	2,092,644	2,302,373	2,092,644
Total
Accumulated Other Comprehensive Loss
Beginning balance	(211,979)	(217,964)	(175,970)	(239,151)
Period change	60,154	(89,306)	24,145	(68,119)
Ending balance	(151,825)	(307,270)	(151,825)	(307,270)
Unrealized Gains (Losses) on Securities Available for Sale
Accumulated Other Comprehensive Loss
Beginning balance			(173,654)	(234,495)
Other comprehensive income before reclassifications			16,905	(71,633)
Amounts reclassified from accumulated other comprehensive loss			7,240	3,644
Period change			24,145	(67,989)
Ending balance	(149,509)	(302,484)	(149,509)	(302,484)
Unrealized Gains (Losses) on Cash Flow Hedges
Accumulated Other Comprehensive Loss
Beginning balance			0	130
Other comprehensive income before reclassifications			0	(142)
Amounts reclassified from accumulated other comprehensive loss			0	12
Period change			0	(130)
Ending balance	0	0	0	0
Unrealized Gains (Losses) on Defined Benefit Plans
Accumulated Other Comprehensive Loss
Beginning balance			(2,316)	(4,786)
Other comprehensive income before reclassifications			0	0
Amounts reclassified from accumulated other comprehensive loss			0	0
Period change			0	0
Ending balance	$ (2,316)	$ (4,786)	$ (2,316)	$ (4,786)