Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating activities:
Net loss (income)	$ (152,668)	$ 7,023	$ 33,893
Adjustments to reconcile net (loss) income to cash provided by operating activities:
(Increase) decrease in accrued interest receivable	(5,190)	(1,200)	577
(Decrease) increase in accrued interest payable	5,277	6,574	578
Loss (gain) on derivative instruments, net	186,949	3,461	(3,044)
Loss on sale of investments, net	5,755	23,373	11,530
Fair value adjustments, net	56	(52)	(75)
Amortization of investment premiums, net	133,690	143,036	157,706
Other amortization and depreciation, net	1,684	1,232	1,287
Stock-based compensation expense	1,205	1,231	1,954
Change in other assets and liabilities, net	(1,412)	(4,118)	42
Net cash and cash equivalents provided by operating activities	175,346	180,560	204,448
Investing activities:
Purchase of investments	(2,991,311)	(1,789,272)	(1,317,959)
Principal payments received on investments	537,481	188,898	307,133
Proceeds from sales of investments	1,033,066	733,064	1,073,093
Principal payments received on mortgage loans held for investment, net	2,103	4,210	3,386
Net (payments) receipts on derivatives, including terminations	(184,920)	(6,135)	21,986
Other investing activities	(121)	(102)	(206)
Net cash and cash equivalents (used in) provided by investing activities	(1,603,702)	(869,337)	87,433
Financing activities:
Borrowings under repurchase agreements	102,505,318	105,236,233	84,876,542
Repayments of repurchase agreement borrowings	(101,020,954)	(104,534,151)	(85,209,592)
Principal payments on non-recourse collateralized financing	(738)	(2,094)	(938)
Proceeds from issuance of preferred stock	19,924	1,599	31,350
Proceeds from issuance of common stock	63,889	41,858	47,182
Cash paid for stock issuance costs	(185)	(10)	(61)
Cash paid for common stock repurchases	(25,034)	0	0
Payments related to tax withholding for stock-based compensation	(296)	(364)	(521)
Dividends paid	(68,042)	(52,790)	(47,532)
Net cash and cash equivalents provided by financing activities	1,473,882	690,281	(303,570)
Net increase (decrease) in cash, cash equivalents, and restricted cash	45,526	1,504	(11,689)
Cash, cash equivalents, and restricted cash at beginning of period	88,704	87,200	98,889
Cash, cash equivalents, and restricted cash at end of period	134,230	88,704	87,200
Supplemental Disclosure of Cash Activity:
Cash paid for interest	$ 108,986	$ 53,205	$ 35,851