SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Gain (Loss) on Settlement of Investments, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accounting Policies [Abstract]
Sale of real estate securities	$ (89,811)	$ (753,713)	$ 205,989
Sale of acquired residential mortgage loans	120,680	(5,662)	153,174
Settlement of derivatives	(172,581)	(74,812)	(129,923)
Liquidated residential mortgage loans	(5,946)	4,644	(4,872)
Sale of REO	(6,622)	(21,925)	(11,521)
Extinguishment of debt	(1,485)	(66,233)	(8,532)
Other	(78,796)	(12,430)	23,666
Total gain (loss) on settlement of investments, net	$ (234,561)	$ (930,131)	$ 227,981