MORTGAGE SERVICING RIGHTS AND MSR FINANCING RECEIVABLES - Schedule of Servicing Fee Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Servicing Asset at Amortized Cost [Line Items]
Realization of cash flows			$ (384,094)
Change in valuation inputs and assumptions, net of realized gains (losses)			(284,756)
Change in fair value of derivative instruments	$ 0	$ (18,505)	0	$ (11,316)
Servicing revenue, net	463,578	433,989	1,278,707	2,269,322
MSRs
Servicing Asset at Amortized Cost [Line Items]
Servicing fee revenue, net and interest income from MSRs and MSR financing receivables	412,386	419,793	1,284,583	1,276,137
Ancillary and other fees	30,258	33,370	93,462	102,904
Servicing fee revenue, net and fees	442,644	453,163	1,378,045	1,379,041
Realization of cash flows	(138,993)	(141,616)	(384,094)	(522,206)
Change in valuation inputs and assumptions, net of realized gains (losses)	159,927	143,174	284,756	1,502,844
Change in fair value of derivative instruments	0	(18,505)	0	(11,316)
Gain (loss) on settlement of derivative instruments	0	(2,227)	0	(79,041)
Servicing revenue, net	$ 463,578	$ 433,989	$ 1,278,707	$ 2,269,322