CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash Flows From Operating Activities:
Net income	$ 413,551	$ 411,637	$ 524,668
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
(Accretion) amortization of investment discounts/premiums, net	58,902	28,633	(25,422)
Accretion (amortization) of deferred financing costs and securitized debt discounts/premiums, net	(29,423)	(13,124)	7,395
Amortization of swaption premium	747	1,476	6,269
Net unrealized losses (gains) on derivatives	106,209	141,162	(47,976)
Margin (paid) received on derivatives	7,250	(320,899)	31,442
Net unrealized losses (gains) on financial instruments at fair value	(409,634)	(46,632)	(111,410)
Net realized losses (gains) on sales of investments	(20,360)	2,743	(9,123)
Net other-than-temporary credit impairment losses	4,853	21,791	61,856
(Gain) loss on extinguishment of debt	(9,318)	(26,376)	35,274
Equity-based compensation expense	10,584	8,797	3,614
Changes in operating assets:
Decrease (increase) in accrued interest receivable, net	6,334	(22,652)	(21,091)
Decrease (increase) in other assets	(20,049)	63,235	18,080
Changes in operating liabilities:
Increase (decrease) in accounts payable and other liabilities	(10,306)	(722)	498
Increase (decrease) in accrued interest payable, net	(44,304)	48,515	13,217
Net cash provided by (used in) operating activities	65,036	297,584	487,291
Cash Flows From Investing Activities:
Acquisition of investments in consolidated VIEs	0	0	(398,261)
Net cash provided by (used in) investing activities	1,236,860	(6,026,067)	(4,331,009)
Cash Flows From Financing Activities:
Proceeds from repurchase agreements	133,892,203	71,279,975	44,120,574
Payments on repurchase agreements	(134,495,789)	(64,499,287)	(42,471,025)
Net proceeds from preferred stock offerings	193,368	251,536	314,429
Payments on repurchase of common stock	0	(14,834)	0
Proceeds from securitized debt borrowings, collateralized by loans held for investment	1,487,286	1,769,539	5,152,469
Payments on securitized debt borrowings, collateralized by loans held for investment	(1,845,272)	(2,613,038)	(2,844,132)
Payments on securitized debt borrowings, collateralized by Non-Agency RMBS	(24,340)	(43,898)	(131,039)
Common dividends paid	(374,256)	(374,396)	(375,771)
Preferred dividends paid	(72,704)	(43,197)	(35,932)
Net cash provided by (used in) financing activities	(1,239,504)	5,712,400	3,729,573
Net increase (decrease) in cash and cash equivalents	62,392	(16,083)	(114,145)
Cash and cash equivalents at beginning of period	47,486	63,569	177,714
Cash and cash equivalents at end of period	109,878	47,486	63,569
Supplemental disclosure of cash flow information:
Interest received	1,427,030	1,279,297	1,092,245
Interest paid	835,041	643,717	512,133
Non-cash investing activities:
Payable for investments purchased	1,256,337	1,136,157	567,440
Receivable for investments sold	446,225	0	0
Net change in unrealized gain (loss) on available-for sale securities	81,504	(170,070)	78,796
Retained beneficial interests	141,484	39,844	0
Acquisition of securities in Consolidated VIEs
Securitized loans held for investment, at fair value	0	0	419,222
Securitized debt at fair value	0	0	(20,961)
Non-cash financing activities:
Dividends declared, not yet paid	98,568	95,986	95,365
Agency MBS portfolio
Cash Flows From Investing Activities:
Purchases	(2,929,500)	(7,917,661)	(1,326,178)
Sales	2,815,394	16,184	743,937
Principal payments	2,237,980	524,989	423,506
Non-agency RMBS Portfolio
Cash Flows From Investing Activities:
Purchases	(373,697)	(133,247)	(15,262)
Sales	38,604	19,928	5,045
Principal payments	415,518	521,109	568,339
Loans held for investment
Cash Flows From Investing Activities:
Sales	1,681,227	754,806	0
Principal payments	1,717,745	1,859,155	1,788,408
Purchases	$ (4,366,411)	$ (1,671,330)	$ (6,120,543)