DERIVATIVES - Summary of Derivative Financial Instruments and Balances (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	$ 20,027,711	$ 19,828,103
Derivative Asset	368,976	357,698
Derivative liabilities	(370,576)	(357,698)
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	19,427,711	19,828,103
Derivative Asset	368,418	357,698
Derivative liabilities	(368,592)	(357,698)
Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	600,000	0
Derivative Asset	558	0
Derivative liabilities	(1,984)	0
Fair Value Hedges | Matched interest rate swaps | Accrued interest and other assets | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	2,218,153	2,206,351
Derivative Asset	5,297	5,057
Derivative liabilities	(168,339)	(147,759)
Fair Value Hedges | Matched interest rate swaps | Accrued interest and other liabilities | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	2,218,153	2,206,351
Derivative Asset	168,165	147,759
Derivative liabilities	(5,297)	(5,057)
Foreign Exchange | Matched interest rate swaps | Accrued interest and other assets | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	7,521,938	7,734,395
Derivative Asset	121,048	111,078
Derivative liabilities	(73,908)	(93,804)
Foreign Exchange | Matched interest rate swaps | Accrued interest and other liabilities | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	7,469,467	7,681,006
Derivative Asset	73,908	93,804
Derivative liabilities	$ (121,048)	$ (111,078)
Cash Flow Hedging | Interest Rate Floor | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Other Liabilities	Other Liabilities
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other Assets	Other Assets
Cash Flow Hedging | Interest Rate Floor | Accrued interest and other liabilities
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	$ 600,000
Cash Flow Hedging | Interest Rate Floor | Accrued interest and other liabilities | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	$ 600,000	$ 0