DERIVATIVES - Gain (Losses) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Derivative [Line Items]
Servicing revenue, net	$ (30,481)	$ 0	$ 0
Gain on originated residential mortgage loans, held for sale, net	(175,135)	133,967	29,152
Other income (loss), net	298,803	(53,467)	(56,143)
Gain (loss) on settlement of investments, net	(172,581)	(74,812)	(129,923)
Total gain (loss)	(79,394)	5,688	(156,914)
Settlement of derivatives	(172,581)	(74,812)	(129,923)
Gain (loss) on settlement of residential mortgage loan origination derivative instruments	240,610	(361,755)	(53,374)
Mortgage Servicing Rights
Derivative [Line Items]
Settlement of derivatives	(34,724)	0	0
TBAs
Derivative [Line Items]
Servicing revenue, net	10,483	0	0
Gain on originated residential mortgage loans, held for sale, net	118,564	(115,243)	3,067
Other income (loss), net	0	0	2,778
Gain (loss) on settlement of investments, net	(36,508)	(72,127)	(121,252)
Treasury futures
Derivative [Line Items]
Servicing revenue, net	(23,961)	0	0
Options on treasury futures
Derivative [Line Items]
Servicing revenue, net	(17,003)	0	0
Interest rate lock commitments
Derivative [Line Items]
Gain on originated residential mortgage loans, held for sale, net	(293,699)	249,183	26,151
Other income (loss), net	0	0	(3)
Forward Loan Sale Commitments
Derivative [Line Items]
Gain on originated residential mortgage loans, held for sale, net	0	27	(66)
Interest rate swaps
Derivative [Line Items]
Other income (loss), net	298,803	(53,467)	(58,918)
Gain (loss) on settlement of investments, net	$ (136,073)	$ (2,685)	$ (8,671)