FINANCIAL DERIVATIVES - Schedule of Net Income/(Expense) Recognized (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Derivative Instruments, Gain (Loss) [Line Items]
Investment securities and cash equivalents	$ 229,611	$ 216,882	$ 648,242	$ 640,515
Loans	242,881	198,459	690,471	555,262
Total Interest Expense	(356,568)	(316,864)	(1,003,318)	(909,564)
Gains/(losses) on financial derivatives	1,515	(1,062)	2,879	(3,618)
Designated as hedge
Derivative Instruments, Gain (Loss) [Line Items]
Investment securities and cash equivalents	229,611	216,882	648,242	640,515
Loans	242,881	198,459	690,471	555,262
Total Interest Expense	(356,568)	(316,864)	(1,003,318)	(909,564)
Gains/(losses) on financial derivatives	1,515	(1,062)	2,879	(3,618)
Total	117,439	97,415	338,274	282,595
Designated as hedge | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on hedged items	(237,881)	10,860	(249,438)	122,647
Net effects of fair value hedging relationships	23,711	14,214	65,276	44,789
Designated as hedge | Fair value hedges: | Income Statement Location [Axis]: us-gaap:GainLossOnDerivativeInstrumentsNetPretax
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on hedged items	0	0	0	0
Net effects of fair value hedging relationships	0	0	0	0
Designated as hedge | Fair value hedges: | Income Statement Location [Axis]: us-gaap:InterestAndDividendIncomeSecurities
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on hedged items	(246,064)	26,624	(329,302)	199,660
Net effects of fair value hedging relationships	17,638	30,052	49,415	88,007
Designated as hedge | Fair value hedges: | Income Statement Location [Axis]: us-gaap:InterestAndFeeIncomeLoansAndLeases
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on hedged items	(165,913)	10,436	(186,905)	64,277
Net effects of fair value hedging relationships	10,305	12,429	26,657	38,574
Designated as hedge | Fair value hedges: | Income Statement Location [Axis]: us-gaap:InterestExpenseOperating
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on hedged items	174,096	(26,200)	266,769	(141,290)
Net effects of fair value hedging relationships	(4,232)	(28,267)	(10,796)	(81,792)
Designated as hedge | Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Interest settlements reclassified from AOCI into net income on derivatives	2,377	3,593	7,307	11,163
Net effects of cash flow hedges	2,377	3,593	7,307	11,163
Designated as hedge | Cash flow hedges: | Income Statement Location [Axis]: us-gaap:GainLossOnDerivativeInstrumentsNetPretax
Derivative Instruments, Gain (Loss) [Line Items]
Interest settlements reclassified from AOCI into net income on derivatives	0	0	0	0
Net effects of cash flow hedges	0	0	0	0
Designated as hedge | Cash flow hedges: | Income Statement Location [Axis]: us-gaap:InterestAndDividendIncomeSecurities
Derivative Instruments, Gain (Loss) [Line Items]
Interest settlements reclassified from AOCI into net income on derivatives	0	0	0	0
Net effects of cash flow hedges	0	0	0	0
Designated as hedge | Cash flow hedges: | Income Statement Location [Axis]: us-gaap:InterestAndFeeIncomeLoansAndLeases
Derivative Instruments, Gain (Loss) [Line Items]
Interest settlements reclassified from AOCI into net income on derivatives	0	0	0	0
Net effects of cash flow hedges	0	0	0	0
Designated as hedge | Cash flow hedges: | Income Statement Location [Axis]: us-gaap:InterestExpenseOperating
Derivative Instruments, Gain (Loss) [Line Items]
Interest settlements reclassified from AOCI into net income on derivatives	2,377	3,593	7,307	11,163
Net effects of cash flow hedges	2,377	3,593	7,307	11,163
Designated as hedge | Interest Rate Swap | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on derivatives	240,131	(10,997)	252,939	(118,976)
Amounts related to interest settlements on derivatives	21,461	14,351	61,775	41,118
Designated as hedge | Interest Rate Swap | Fair value hedges: | Income Statement Location [Axis]: us-gaap:GainLossOnDerivativeInstrumentsNetPretax
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on derivatives	0	0	0	0
Amounts related to interest settlements on derivatives	0	0	0	0
Designated as hedge | Interest Rate Swap | Fair value hedges: | Income Statement Location [Axis]: us-gaap:InterestAndDividendIncomeSecurities
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on derivatives	246,656	(27,117)	329,361	(200,349)
Amounts related to interest settlements on derivatives	17,046	30,545	49,356	88,696
Designated as hedge | Interest Rate Swap | Fair value hedges: | Income Statement Location [Axis]: us-gaap:InterestAndFeeIncomeLoansAndLeases
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on derivatives	168,181	(10,864)	189,502	(63,445)
Amounts related to interest settlements on derivatives	8,037	12,857	24,060	37,742
Designated as hedge | Interest Rate Swap | Fair value hedges: | Income Statement Location [Axis]: us-gaap:InterestExpenseOperating
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on derivatives	(174,706)	26,984	(265,924)	144,818
Amounts related to interest settlements on derivatives	(3,622)	(29,051)	(11,641)	(85,320)
No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(losses) on financial derivatives	1,515	(1,062)	2,879	(3,618)
No hedge designation | Income Statement Location [Axis]: us-gaap:GainLossOnDerivativeInstrumentsNetPretax
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(losses) on financial derivatives	1,515	(1,062)	2,879	(3,618)
No hedge designation | Income Statement Location [Axis]: us-gaap:InterestAndDividendIncomeSecurities
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(losses) on financial derivatives	0	0	0	0
No hedge designation | Income Statement Location [Axis]: us-gaap:InterestAndFeeIncomeLoansAndLeases
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(losses) on financial derivatives	0	0	0	0
No hedge designation | Income Statement Location [Axis]: us-gaap:InterestExpenseOperating
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(losses) on financial derivatives	0	0	0	0
No hedge designation | Interest Rate Swap
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(losses) on financial derivatives	1,746	474	924	(3,063)
Interest expense on interest rate swaps	315	(707)	1,840	(597)
No hedge designation | Interest Rate Swap | Income Statement Location [Axis]: us-gaap:GainLossOnDerivativeInstrumentsNetPretax
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(losses) on financial derivatives	1,746	474	924	(3,063)
Interest expense on interest rate swaps	315	(707)	1,840	(597)
No hedge designation | Interest Rate Swap | Income Statement Location [Axis]: us-gaap:InterestAndDividendIncomeSecurities
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(losses) on financial derivatives	0	0	0	0
Interest expense on interest rate swaps	0	0	0	0
No hedge designation | Interest Rate Swap | Income Statement Location [Axis]: us-gaap:InterestAndFeeIncomeLoansAndLeases
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(losses) on financial derivatives	0	0	0	0
Interest expense on interest rate swaps	0	0	0	0
No hedge designation | Interest Rate Swap | Income Statement Location [Axis]: us-gaap:InterestExpenseOperating
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(losses) on financial derivatives	0	0	0	0
Interest expense on interest rate swaps	0	0	0	0
No hedge designation | Treasury futures
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(losses) on financial derivatives	(546)	(829)	115	42
No hedge designation | Treasury futures | Income Statement Location [Axis]: us-gaap:GainLossOnDerivativeInstrumentsNetPretax
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(losses) on financial derivatives	(546)	(829)	115	42
No hedge designation | Treasury futures | Income Statement Location [Axis]: us-gaap:InterestAndDividendIncomeSecurities
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(losses) on financial derivatives	0	0	0	0
No hedge designation | Treasury futures | Income Statement Location [Axis]: us-gaap:InterestAndFeeIncomeLoansAndLeases
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(losses) on financial derivatives	0	0	0	0
No hedge designation | Treasury futures | Income Statement Location [Axis]: us-gaap:InterestExpenseOperating
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(losses) on financial derivatives	$ 0	$ 0	$ 0	$ 0