CHANGE IN ACCUMULATED OTHER COMPREHENSIVE LOSS - Schedule of Components of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance			$ 2,589,752
Other comprehensive income (loss)	$ 44,166	$ 138,945	140,571	$ 82,680
Amounts reclassified from accumulated other comprehensive loss	3,301	3,916	9,617	11,294
Total other comprehensive income	47,467	142,861	150,188	93,974
Ending balance	2,753,273		2,753,273
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(522,156)	(642,878)	(624,877)	(593,991)
Total other comprehensive income	47,467	142,861	150,188	93,974
Ending balance	(474,689)	(500,017)	(474,689)	(500,017)
Net change in investment securities available-for-sale
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(445,064)	(549,039)	(537,789)	(499,932)
Other comprehensive income (loss)	44,395	128,223	137,120	79,116
Amounts reclassified from accumulated other comprehensive loss	0	0	0	0
Total other comprehensive income	44,395	128,223	137,120	79,116
Ending balance	(400,669)	(420,816)	(400,669)	(420,816)
Net change in investment securities held-to-maturity
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(69,950)	(84,046)	(76,405)	(91,523)
Other comprehensive income (loss)	0	0	0	0
Amounts reclassified from accumulated other comprehensive loss	3,370	3,965	9,825	11,442
Total other comprehensive income	3,370	3,965	9,825	11,442
Ending balance	(66,580)	(80,081)	(66,580)	(80,081)
Net change in defined benefit plan
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(3,937)	(4,790)	(3,815)	(4,614)
Other comprehensive income (loss)	7	(4)	24	(81)
Amounts reclassified from accumulated other comprehensive loss	(69)	(49)	(208)	(148)
Total other comprehensive income	(62)	(53)	(184)	(229)
Ending balance	(3,999)	(4,843)	(3,999)	(4,843)
Net change in fair value of derivatives used for cash flow hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(2,982)	(5,423)	(7,297)	1,597
Other comprehensive income (loss)	(215)	10,722	4,100	3,702
Amounts reclassified from accumulated other comprehensive loss	0	0	0	0
Total other comprehensive income	(215)	10,722	4,100	3,702
Ending balance	(3,197)	5,299	(3,197)	5,299
Net change in equity method investments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(223)	420	429	481
Other comprehensive income (loss)	(21)	4	(673)	(57)
Amounts reclassified from accumulated other comprehensive loss	0	0	0	0
Total other comprehensive income	(21)	4	(673)	(57)
Ending balance	$ (244)	$ 424	$ (244)	$ 424