INTEREST INCOME AND INTEREST EXPENSE - Components of Company's Interest Income and Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Interest income
Agency securities	$ 497,135	$ 255,801	$ 1,020,086	$ 883,455
Residential credit securities	30,037	19,477	52,159	36,457
Residential mortgage loans	91,648	38,963	165,136	76,072
Commercial investment portfolio	26,575	69,663	63,858	151,264
Reverse repurchase agreements	220	2	226	36
Total interest income	645,615	383,906	1,301,465	1,147,284
Interest expense
Repurchase agreements	105,608	29,140	132,487	71,725
Debt issued by securitization vehicles	50,303	23,216	84,928	49,492
Participations issued	9,379	1,739	15,231	2,336
Other	5,185	6,952	12,751	13,467
Total interest expense	170,475	61,047	245,397	137,020
Net interest income	$ 475,140	$ 322,859	$ 1,056,068	$ 1,010,264