LOANS - Investment Loan Activity (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($)
SEC Schedule, 12-29, Real Estate Companies, Investment in Movement in Mortgage Loans on Real Estate [Roll Forward]
Beginning balance January 1, 2022	$ 4,242,043	[1]
Ending balance December 31, 2022	1,809,832	[1]
Transfer of residential loans to securitization vehicles, carrying value, noncash	6,100,000
Total
SEC Schedule, 12-29, Real Estate Companies, Investment in Movement in Mortgage Loans on Real Estate [Roll Forward]
Beginning balance January 1, 2022	4,241,063
Purchases / originations	6,169,044
Sales and transfers	(8,008,553)
Principal payments	(342,779)
Gains / (losses)	(243,450)
(Amortization) / accretion	(5,493)
Ending balance December 31, 2022	1,809,832
Residential
SEC Schedule, 12-29, Real Estate Companies, Investment in Movement in Mortgage Loans on Real Estate [Roll Forward]
Beginning balance January 1, 2022	2,272,072
Purchases / originations	5,983,775
Sales and transfers	(6,106,109)
Principal payments	(111,589)
Gains / (losses)	(220,130)
(Amortization) / accretion	(8,187)
Ending balance December 31, 2022	1,809,832
Corporate Debt
SEC Schedule, 12-29, Real Estate Companies, Investment in Movement in Mortgage Loans on Real Estate [Roll Forward]
Beginning balance January 1, 2022	1,968,991
Purchases / originations	185,269
Sales and transfers	(1,902,444)
Principal payments	(231,190)
Gains / (losses)	(23,320)
(Amortization) / accretion	2,694
Ending balance December 31, 2022	$ 0

[1] (3) Includes $1.3 million and $2.3 million of residential mortgage loans held for sale at December 31, 2022 and 2021, respectively.