FAIR VALUE MEASUREMENTS - Financial Assets Measured at Fair Value on a Recurring Basis using Level 3 Inputs (Details) - Recurring Basis - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning	$ 16,927,414	$ 14,826,220	$ 17,356,207	$ 14,427,743
Transfers:
Transfers out of Level 3	(372,985)	(149,919)	(786,111)	(149,919)
Transfers to Level 3		1,283	23,890	1,389
Computershare Acquisition (Note 3)		696,462		696,462
Gain (Loss) Included in Net Income:
Credit losses on securities	(705)	(252)	(603)	(914)
Included in servicing revenue	(194,819)	(76,924)	(733,101)	7,251
Other factors	29,120	17,059	54,163	31,356
Instrument-specific credit risk	(12,294)	8,070	(28,656)	(5,184)
Gain (loss) on settlement of investments, net		(656)		(620)
Other income (loss), net	(18,275)	(1,171)	19,980	(4,390)
Gains (losses) included in OCI	3,210	(4,211)	7,950	(3,474)
Interest income	24,680	26,005	47,290	54,561
Purchases, Sales and Repayments:
Purchases, net	346,337	407,631	696,597	855,365
Sales and settlement fundings	(23,165)	(36,048)	(40,763)	(49,030)
Proceeds from repayments	(1,086,652)	(964,006)	(2,123,730)	(1,969,025)
Originations and other	1,345,097	870,188	2,473,850	1,728,160
Balance, ending	16,966,963	15,619,731	16,966,963	15,619,731
Excess MSRs
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning	354,923	255,111	369,162	271,150
Transfers:
Transfers out of Level 3	0	0	0	0
Transfers to Level 3		0	0	0
Computershare Acquisition (Note 3)		(1,032)		(1,032)
Gain (Loss) Included in Net Income:
Credit losses on securities	0	0	0	0
Included in servicing revenue	0	0	0	0
Other factors	(690)	22,914	(1,605)	21,047
Instrument-specific credit risk	0	0	0	0
Gain (loss) on settlement of investments, net		(656)		(656)
Other income (loss), net	0	0	0	0
Gains (losses) included in OCI	0	0	0	0
Interest income	9,109	8,076	13,299	10,522
Purchases, Sales and Repayments:
Purchases, net	0	122,887	0	122,887
Sales and settlement fundings	(45)	0	(45)	0
Proceeds from repayments	(17,620)	(11,694)	(35,134)	(28,312)
Originations and other	0	0	0	0
Balance, ending	345,677	395,606	345,677	395,606
MSRs And MSR Financing Receivables
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning	10,133,041	8,706,723	10,321,671	8,405,938
Transfers:
Transfers out of Level 3	0	0	0	0
Transfers to Level 3		0	0	0
Computershare Acquisition (Note 3)		697,494		697,494
Gain (Loss) Included in Net Income:
Credit losses on securities	0	0	0	0
Included in servicing revenue	(194,819)	(76,924)	(733,101)	7,251
Other factors	0	0	0	0
Instrument-specific credit risk	0	0	0	0
Gain (loss) on settlement of investments, net		0		0
Other income (loss), net	0	0	0	0
Gains (losses) included in OCI	0	0	0	0
Interest income	0	0	0	0
Purchases, Sales and Repayments:
Purchases, net	0	0	0	0
Sales and settlement fundings	1,860	1,733	2,524	2,404
Proceeds from repayments	0	0	0	0
Originations and other	419,981	364,305	768,969	580,244
Balance, ending	10,360,063	9,693,331	10,360,063	9,693,331
Servicer Advances
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning	321,531	374,511	339,646	376,881
Transfers:
Transfers out of Level 3	0	(7,873)	0	(7,873)
Transfers to Level 3		0	0	0
Computershare Acquisition (Note 3)		0		0
Gain (Loss) Included in Net Income:
Credit losses on securities	0	0	0	0
Included in servicing revenue	0	0	0	0
Other factors	166	(1,727)	(1,527)	6,388
Instrument-specific credit risk	0	0	0	0
Gain (loss) on settlement of investments, net		0		0
Other income (loss), net	0	0	0	0
Gains (losses) included in OCI	0	0	0	0
Interest income	5,245	5,939	10,600	13,254
Purchases, Sales and Repayments:
Purchases, net	164,021	187,996	350,377	400,652
Sales and settlement fundings	0	0	0	0
Proceeds from repayments	(177,977)	(201,626)	(386,110)	(432,082)
Originations and other	0	0	0	0
Balance, ending	312,986	357,220	312,986	357,220
Non-Agency
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning	639,458	581,539	552,797	577,543
Transfers:
Transfers out of Level 3	0	0	0	0
Transfers to Level 3		0	0	0
Computershare Acquisition (Note 3)		0		0
Gain (Loss) Included in Net Income:
Credit losses on securities	(705)	(252)	(603)	(914)
Included in servicing revenue	0	0	0	0
Other factors	2,072	(2,860)	3,976	0
Instrument-specific credit risk	0	0	0	0
Gain (loss) on settlement of investments, net		0		0
Other income (loss), net	0	939	0	939
Gains (losses) included in OCI	3,210	278	7,950	1,880
Interest income	9,549	6,373	16,572	14,869
Purchases, Sales and Repayments:
Purchases, net	113,890	0	210,826	13,900
Sales and settlement fundings	0	0	0	0
Proceeds from repayments	(28,331)	(37,970)	(52,375)	(60,170)
Originations and other	0	0	0	0
Balance, ending	739,143	548,047	739,143	548,047
CLOs And Consolidated Funds
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning	457,276	211,996	810,431	226,486
Transfers:
Transfers out of Level 3	(372,985)	0	(785,253)	0
Transfers to Level 3		0	21,809	0
Computershare Acquisition (Note 3)		0		0
Gain (Loss) Included in Net Income:
Credit losses on securities	0	0	0	0
Included in servicing revenue	0	0	0	0
Other factors	0	0	0	0
Instrument-specific credit risk	0	0	0	0
Gain (loss) on settlement of investments, net		0		36
Other income (loss), net	(27,843)	4,646	404	4,646
Gains (losses) included in OCI	0	(4,489)	0	(5,354)
Interest income	0	0	0	0
Purchases, Sales and Repayments:
Purchases, net	61,459	62,938	88,157	66,617
Sales and settlement fundings	(30,054)	0	(47,695)	0
Proceeds from repayments	0	(13,599)	0	(30,939)
Originations and other	0	0	0	0
Balance, ending	87,853	261,492	87,853	261,492
Residential Mortgage Loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning	444,684	703,549	455,726	513,381
Transfers:
Transfers out of Level 3	0	(142,046)	(858)	(142,046)
Transfers to Level 3		1,283	2,081	1,389
Computershare Acquisition (Note 3)		0		0
Gain (Loss) Included in Net Income:
Credit losses on securities	0	0	0	0
Included in servicing revenue	0	0	0	0
Other factors	2,828	(874)	12,840	8,748
Instrument-specific credit risk	(653)	19,919	(6,450)	15,893
Gain (loss) on settlement of investments, net		0		0
Other income (loss), net	322	2,524	1,760	4,348
Gains (losses) included in OCI	0	0	0	0
Interest income	0	0	0	0
Purchases, Sales and Repayments:
Purchases, net	299	30,487	538	246,892
Sales and settlement fundings	0	(43,766)	(7,216)	(61,532)
Proceeds from repayments	(16,117)	(16,044)	(32,473)	(32,086)
Originations and other	(1,169)	(170,445)	4,246	(170,400)
Balance, ending	430,194	384,587	430,194	384,587
Consumer Loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning	554,168	1,103,799	665,565	1,274,005
Transfers:
Transfers out of Level 3	0	0	0	0
Transfers to Level 3		0	0	0
Computershare Acquisition (Note 3)		0		0
Gain (Loss) Included in Net Income:
Credit losses on securities	0	0	0	0
Included in servicing revenue	0	0	0	0
Other factors	(2,514)	(12,599)	(13,323)	(19,755)
Instrument-specific credit risk	(4,384)	(8,673)	(6,388)	(31,634)
Gain (loss) on settlement of investments, net		0		0
Other income (loss), net	0	0	0	0
Gains (losses) included in OCI	0	0	0	0
Interest income	777	5,826	6,700	15,978
Purchases, Sales and Repayments:
Purchases, net	0	0	0	0
Sales and settlement fundings	5,074	5,985	11,669	10,098
Proceeds from repayments	(87,890)	(147,971)	(198,992)	(302,325)
Originations and other	0	0	0	0
Balance, ending	465,231	946,367	465,231	946,367
Other Assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning	748,583	504,248	700,942	549,446
Transfers:
Transfers out of Level 3	0	0	0	0
Transfers to Level 3		0	0	0
Computershare Acquisition (Note 3)		0		0
Gain (Loss) Included in Net Income:
Credit losses on securities	0	0	0	0
Included in servicing revenue	0	0	0	0
Other factors	19,202	(1,650)	42,736	(67)
Instrument-specific credit risk	0	0	0	0
Gain (loss) on settlement of investments, net		0		0
Other income (loss), net	9,246	(9,280)	17,816	(14,323)
Gains (losses) included in OCI	0	0	0	0
Interest income	0	(209)	119	(62)
Purchases, Sales and Repayments:
Purchases, net	6,668	3,323	46,699	4,417
Sales and settlement fundings	0	0	0	0
Proceeds from repayments	(20,149)	(4,720)	(44,762)	(47,638)
Originations and other	(2,959)		(2,959)	(61)
Balance, ending	760,591	491,712	760,591	491,712
Residential Transition Loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning	3,273,750	2,384,744	3,140,267	2,232,913
Transfers:
Transfers out of Level 3	0	0	0	0
Transfers to Level 3		0	0	0
Computershare Acquisition (Note 3)		0		0
Gain (Loss) Included in Net Income:
Credit losses on securities	0	0	0	0
Included in servicing revenue	0	0	0	0
Other factors	8,056	13,855	11,066	14,995
Instrument-specific credit risk	(7,257)	(3,176)	(15,818)	10,557
Gain (loss) on settlement of investments, net		0		0
Other income (loss), net	0	0	0	0
Gains (losses) included in OCI	0	0	0	0
Interest income	0	0	0	0
Purchases, Sales and Repayments:
Purchases, net	0	0	0	0
Sales and settlement fundings	0	0	0	0
Proceeds from repayments	(738,568)	(530,382)	(1,373,884)	(1,035,473)
Originations and other	929,244	676,328	1,703,594	1,318,377
Balance, ending	$ 3,465,225	$ 2,541,369	$ 3,465,225	$ 2,541,369