OTHER ASSETS AND LIABILITIES, GENERAL AND ADMINISTRATIVE, AND OTHER ITEMS - Schedule of Gain (Loss) on Settlement of Investments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Gain on Settlement of Investments, Net
Gain (loss) on sale of real estate securities	$ (24,708)	$ (6,669)	$ (25,691)	$ (761,209)
Gain (loss) on sale of acquired residential mortgage loans	19,198	(47,330)	49,597	(12,094)
Gain (loss) on settlement of derivatives	(49,256)	(25,195)	(76,629)	(109,907)
Gain (loss) on liquidated residential mortgage loans	(268)	3,220	629	2,381
Gain (loss) on sale of REO	(239)	443	(4,185)	1,616
Gain (loss) on extinguishment of debt	89	0	83	1,461
Other gain (loss)	(21,120)	565	(32,086)	3,214
Total gain (loss) on settlement of investments, net	$ (76,304)	$ (74,966)	$ (88,282)	$ (874,538)