MORTGAGE SERVICING RIGHTS AND MSR FINANCING RECEIVABLES - Schedule of Servicing Fee Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Schedule of Investments in Mortgage Servicing Rights [Line Items]
Change in valuation inputs and assumptions	$ (1,449,134)	$ (680,431)
(Gain) loss realized	(5,093)	(2,410)
Gain (loss) on settlement of derivative instruments	374,464	(172,581)	$ (74,812)
Servicing revenue, net	2,564,714	984,201	(526,637)
Excess Spread Financing
Schedule of Investments in Mortgage Servicing Rights [Line Items]
Realization of cash flows		(3,900)	(8,700)
Change in valuation inputs and assumptions		300	5,500
MSRs
Schedule of Investments in Mortgage Servicing Rights [Line Items]
Servicing fee revenue, net and interest income from MSRs and MSR financing receivables	1,699,587	1,446,509	1,457,211
Ancillary and other fees	132,377	113,045	185,061
Servicing fee revenue and fees, net	1,831,964	1,559,554	1,642,272
Realization of cash flows	(631,120)	(1,192,646)	(1,583,628)
Change in valuation inputs and assumptions	1,449,134	680,088	(585,928)
Change in fair value of derivative instruments	(11,316)	(30,481)	0
(Gain) loss realized	5,093	2,410	647
Gain (loss) on settlement of derivative instruments	(79,041)	(34,724)	0
Servicing revenue, net	$ 2,564,714	$ 984,201	$ (526,637)