DERIVATIVES AND HEDGING - Schedule of Derivatives and Hedges of Notional Amounts (Details) - Not Designated as Hedging Instrument - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Interest rate swaps
Derivative [Line Items]
Derivative asset, notional amount	$ 700,000	$ 7,979,988
Interest rate swaps | TBAs, short position
Derivative [Line Items]
Notional amount	$ 0	$ 0
Derivative, cap interest rate	0.00%	0.00%
Weighted average maturity	0 months	0 months
Interest rate swaps | TBAs, long position
Derivative [Line Items]
Notional amount	$ 700,000	$ 8,000,000
Derivative, cap interest rate	4.60%	2.50%
Weighted average maturity	32 months	32 months
IRLCs
Derivative [Line Items]
Derivative asset, notional amount	$ 3,734,933	$ 2,757,060
Treasury short sales
Derivative [Line Items]
Derivative liability, notional amount	2,985,000	1,800,000
TBAs | TBAs, short position
Derivative [Line Items]
Derivative liability, notional amount	7,918,900	6,013,100
Other commitments
Derivative [Line Items]
Derivative liability, notional amount	$ 23,021	$ 0