Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating activities:
Net income (loss)	$ 177,530	$ (152,668)	$ 7,023
Adjustments to reconcile net income (loss) to cash provided by operating activities:
Loss on derivative instruments, net	172,290	186,949	3,461
(Gain) loss on sale of investments, net	(308,084)	5,755	23,373
(Gain) loss on investments, net	(20)	56	(52)
Amortization of investment premiums, net	126,395	133,690	143,036
Other amortization and depreciation, net	1,989	1,684	1,232
Stock-based compensation expense	1,823	1,205	1,231
Decrease (increase) in accrued interest receivable	11,821	(5,190)	(1,200)
(Decrease) increase in accrued interest payable	(14,175)	5,277	6,574
Change in other assets and liabilities, net	4,383	(1,412)	(4,118)
Net cash provided by operating activities	173,952	175,346	180,560
Investing activities:
Purchase of investments	(2,436,953)	(2,991,311)	(1,789,272)
Principal payments received on investments	474,731	537,481	188,898
Proceeds from sales of investments	4,491,873	1,033,066	733,064
Principal payments received on mortgage loans held for investment	2,854	2,103	4,210
Net payments on derivatives, including terminations	(184,857)	(184,920)	(6,135)
Other investing activities	0	(121)	(102)
Net cash provided by (used in) investing activities	2,347,648	(1,603,702)	(869,337)
Financing activities:
Borrowings under repurchase agreements	31,054,242	102,505,318	105,236,233
Repayments of repurchase agreement borrowings	(33,369,427)	(101,020,954)	(104,534,151)
Principal payments on non-recourse collateralized financing	(2,646)	(738)	(2,094)
Proceeds from issuance of preferred stock	107,843	19,924	1,599
Proceeds from issuance of common stock	9,891	63,889	41,858
Payments for Repurchase of Redeemable Preferred Stock	100,000	0	0
Cash paid for stock issuance costs	0	(185)	(10)
Payments for Repurchase of Common Stock	372	25,034	0
Payments related to tax withholding for stock-based compensation	(245)	(296)	(364)
Dividends paid	(52,437)	(68,042)	(52,790)
Net cash (used in) provided by financing activities	(2,353,151)	1,473,882	690,281
Net increase in cash, cash equivalents, and restricted cash	168,449	45,526	1,504
Cash, cash equivalents, and restricted cash at beginning of period	134,230	88,704	87,200
Cash, cash equivalents, and restricted cash at end of period	302,679	134,230	88,704
Supplemental Disclosure of Cash Activity:
Cash paid for interest	$ 46,054	$ 108,986	$ 53,205