CONSOLIDATED STATEMENTS OF CASH FLOWS $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Cash Flows from Operating Activities
Net income (loss)	$ 364,101	$ (70,536)	$ 353,057
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Amortization of mortgage-backed and credit risk transfer securities premiums and (discounts), net	46,243	42,608	67,152
Realized and unrealized (gain) loss on derivative instruments, net	570,595	(14,738)	(95,231)
Realized and unrealized (gain) loss on credit derivatives, net	12,490	22,629	(28,305)
(Gain) loss on investments, net	(624,466)	327,700	19,704
(Gain) loss from investments in unconsolidated ventures in excess of distributions received	(490)	392	1,972
Other amortization	(23,207)	(25,184)	(23,888)
Net loss on extinguishment of debt	0	26	6,814
(Gain) loss on foreign currency transactions, net	0	1,038	(4,103)
Changes in operating assets and liabilities:
Increase in operating assets	(8,096)	(155)	(7,774)
Increase in operating liabilities	6,189	20,484	1,203
Net cash provided by operating activities	343,359	304,264	290,601
Cash Flows from Investing Activities
Purchase of mortgage-backed and credit risk transfer securities	(9,244,391)	(6,217,723)	(6,277,918)
Distributions from (contributions to) investments in unconsolidated ventures, net	1,346	1,121	6,220
Change in other assets	10,327	(51,017)	(3,457)
Principal payments from mortgage-backed and credit risk transfer securities	2,189,327	1,986,930	2,401,951
Proceeds from sale of mortgage-backed and credit risk transfer securities	3,311,884	4,749,807	625,540
Settlement (termination) of futures, forwards, swaps, and TBAs, net	(597,077)	(2,830)	67,838
Net change in due from counterparties and collateral held payable on derivative instruments	(3,174)	(3,994)	5,627
Principal payments from commercial loans held-for-investment	7,527	160,934	90,713
Origination and advances of commercial loans, net of origination fees	0	(1,677)	(4,799)
Net cash (used in) provided by investing activities	(4,324,231)	621,551	(3,088,285)
Cash Flows from Financing Activities
Proceeds from issuance of common stock	509,075	0	0
Repurchase of common stock	0	(1,144)	0
Proceeds from issuance of preferred stock	0	0	278,226
Proceeds from repurchase agreements	131,624,461	136,573,821	146,886,038
Principal repayments of repurchase agreements	(127,694,642)	(137,052,138)	(143,964,490)
Extinguishment of exchangeable senior notes	0	(143,433)	(262,069)
Net change in due from counterparties and collateral held payable on repurchase agreements	(32,557)	0	0
Payments of deferred costs	(346)	(167)	(116)
Purchase of Operating Partnership units from non-controlling interest	0	(21,764)	0
Payments of dividends and distributions	(271,234)	(234,374)	(212,692)
Net cash provided by (used in) financing activities	4,134,757	(879,199)	2,724,897
Net change in cash, cash equivalents and restricted cash	153,885	46,616	(72,787)
Cash, cash equivalents, and restricted cash beginning of period	135,617	89,001	161,788
Cash, cash equivalents, and restricted cash end of period	289,502	135,617	89,001
Supplement Disclosure of Cash Flow Information
Interest paid	489,661	344,422	220,299
Non-cash Investing and Financing Activities Information
Net change in unrealized gain (loss) on mortgage-backed and credit risk transfer securities	93,037	(17,262)	(8,377)
Dividends and distributions declared not paid	74,841	49,578	50,193
(Decrease) increase in unsettled to-be-announced (“TBA”) securities and related payable	(32,530)	132,087	0
Net change in investment related receivable (payable) excluding TBA securities	5,724	(2,999)	(25,948)
Net change in repurchase agreements, not settled	0	0	(1,416)
Change in foreign currency translation adjustment on other investments	$ 1,158	$ 447	$ (863)