CHANGE IN ACCUMULATED OTHER COMPREHENSIVE (LOSS) INCOME - Components of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	$ 1,939,099
Other comprehensive (loss) income before reclassifications	(275,861)	$ (69,316)
Less: Amounts reclassified from accumulated other comprehensive (loss) income	(151)	(393)
Net current-period other comprehensive (loss) income	(276,012)	(69,709)
Ending Balance	2,520,463
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(37,768)	56,007
Ending Balance	(313,780)	(13,702)
Net change in investment securities available-for-sale
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(33,873)	59,882
Other comprehensive (loss) income before reclassifications	(275,918)	(69,589)
Less: Amounts reclassified from accumulated other comprehensive (loss) income	0	(250)
Net current-period other comprehensive (loss) income	(275,918)	(69,839)
Ending Balance	(309,791)	(9,957)
Net change in investment securities held-to-maturity
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	175	276
Other comprehensive (loss) income before reclassifications	56	0
Less: Amounts reclassified from accumulated other comprehensive (loss) income	(84)	(16)
Net current-period other comprehensive (loss) income	(28)	(16)
Ending Balance	147	260
Net change in defined benefit plan
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(4,691)	(4,788)
Other comprehensive (loss) income before reclassifications	0	0
Less: Amounts reclassified from accumulated other comprehensive (loss) income	(27)	(16)
Net current-period other comprehensive (loss) income	(27)	(16)
Ending Balance	(4,718)	(4,804)
Net change in fair value of derivatives used for cash flow hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	268	646
Other comprehensive (loss) income before reclassifications	1	0
Less: Amounts reclassified from accumulated other comprehensive (loss) income	(40)	(111)
Net current-period other comprehensive (loss) income	(39)	(111)
Ending Balance	229	535
Net change in equity method investments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	353	(9)
Other comprehensive (loss) income before reclassifications	0	273
Less: Amounts reclassified from accumulated other comprehensive (loss) income	0	0
Net current-period other comprehensive (loss) income	0	273
Ending Balance	$ 353	$ 264

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount after tax, before reclassification adjustments, of other comprehensive income (loss), attributable to parent.

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Amount after tax of other comprehensive income (loss) attributable to parent entity.

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Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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