CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash Flows From Operating Activities:
Net income (loss)	$ 652,380	$ (58,381)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
(Accretion) amortization of investment discounts/premiums, net	61,158	93,365
Accretion (amortization) of deferred financing costs, debt issuance costs, and securitized debt discounts/premiums, net	9,268	(41,102)
Net unrealized losses (gains) on derivatives	0	(201,000)
Margin (paid) received on derivatives	0	325,594
Net unrealized losses (gains) on financial instruments at fair value	(545,643)	172,042
Net realized losses (gains) on sales of investments	(45,313)	(167,275)
Net increase (decrease) in provision for credit losses	(58)	167
(Gain) loss on extinguishment of debt	284,535	55,338
Equity-based compensation expense	4,993	4,112
Changes in operating assets:
Decrease (increase) in accrued interest receivable, net	7,145	30,381
Decrease (increase) in other assets	(22,439)	(22,507)
Changes in operating liabilities:
Increase (decrease) in accounts payable and other liabilities	24,626	17,736
Increase (decrease) in accrued interest payable, net	(20,564)	(27,842)
Net cash provided by (used in) operating activities	410,088	180,628
Cash Flows From Investing Activities:
Net cash provided by (used in) investing activities	1,840,841	8,137,066
Cash Flows From Financing Activities:
Proceeds from secured financing agreements	36,235,601	74,264,849
Payments on secured financing agreements	(37,087,294)	(83,030,677)
Payments on repurchase of common stock	(1,828)	(22,066)
Proceeds from securitized debt borrowings, collateralized by Loans held for investment	5,060,056	2,061,895
Payments on securitized debt borrowings, collateralized by Loans held for investment	(5,846,212)	(1,379,866)
Payments on securitized debt borrowings, collateralized by Non-Agency RMBS	(18,495)	(13,852)
Payments on convertible debt purchases	(36,892)	0
Net proceeds from issuance of convertible debt	0	361,139
Purchase of capped call	0	(33,750)
Settlement of warrants	(220,945)	0
Common dividends paid	(220,242)	(254,214)
Preferred dividends paid	(55,313)	(55,313)
Net cash provided by (used in) financing activities	(2,191,564)	(8,101,855)
Net increase (decrease) in cash and cash equivalents	59,365	215,839
Cash and cash equivalents at beginning of period	269,090	109,878
Cash and cash equivalents at end of period	328,455	325,717
Supplemental disclosure of cash flow information:
Interest received	784,688	917,156
Interest paid	271,325	464,147
Non-cash investing activities:
Payable for investments purchased	192,552	614,583
Net change in unrealized gain (loss) on available-for sale securities	(119,181)	(153,355)
Retained beneficial interests	24,891	21,943
Non-cash financing activities:
Dividends declared, not yet paid	85,255	76,362
Conversion of convertible debt	37,340	290,531
Agency MBS portfolio
Cash Flows From Investing Activities:
Purchases	(182,350)	(385,014)
Sales	201,653	7,201,313
Principal payments	509,693	705,272
Non-agency RMBS Portfolio
Cash Flows From Investing Activities:
Purchases	(9,766)	(22,859)
Sales	47,674	142,534
Principal payments	239,348	191,294
Loans held for investment
Cash Flows From Investing Activities:
Sales	1,653,260	703,342
Principal payments	1,982,400	1,384,331
Purchases	$ (2,601,071)	$ (1,783,147)