INTEREST INCOME AND INTEREST EXPENSE - Components of Company's Interest Income and Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Interest income
Agency securities	$ 517,528	$ 299,898	$ 1,537,614	$ 1,183,353
Residential credit securities	41,388	20,774	93,547	57,231
Residential mortgage loans	109,977	45,801	275,113	121,873
Commercial investment portfolio	8,853	46,494	72,711	197,758
Reverse repurchase agreements	742	5	968	41
Total interest income	678,488	412,972	1,979,953	1,560,256
Interest expense
Repurchase agreements	324,573	22,397	457,060	94,122
Debt issued by securitization vehicles	64,593	18,740	149,521	68,232
Participations issued	9,727	2,578	24,958	4,914
Other	1,598	6,723	14,349	20,190
Total interest expense	400,491	50,438	645,888	187,458
Net interest income	$ 277,997	$ 362,534	$ 1,334,065	$ 1,372,798