DERIVATIVES - Derivatives Notional Amount (Details) - Not Designated as Hedging Instrument - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2023	Dec. 31, 2022
Interest rate swaps
Derivative [Line Items]
Derivative asset, notional amount	$ 22,565,000	$ 23,085,000
Interest rate swaps | TBAs, short position
Derivative [Line Items]
Notional amount	$ 2,400,000	$ 0
Derivative, cap interest rate	3.40%	0.00%
Weighted average maturity	40 months	0 months
Interest rate swaps | TBAs, long position
Derivative [Line Items]
Notional amount	$ 20,200,000	$ 23,100,000
Derivative, cap interest rate	2.50%	1.90%
Weighted average maturity	38 months	35 months
Interest rate lock commitments
Derivative [Line Items]
Derivative asset, notional amount	$ 2,704,543	$ 2,647,747
TBAs | TBAs, short position
Derivative [Line Items]
Derivative liability, notional amount	7,104,300	8,473,221
TBAs | TBAs, long position
Derivative [Line Items]
Derivative liability, notional amount	$ 0	$ 31,500