Consolidated Statements of Cash Flows - USD ($)	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Operating activities:
Net (loss) income	$ (171,199,000)	$ 59,959,000
Adjustments to reconcile net (loss) income to cash provided by operating activities:
(Increase) decrease in accrued interest receivable	(4,273,000)	493,000
Increase in accrued interest payable	5,599,000	1,735,000
Loss (gain) on derivative instruments, net	179,233,000	(59,021,000)
Loss on sale of investments, net	10,360,000	16,219,000
Fair value adjustments, net	29,000	(56,000)
Amortization of investment premiums, net	63,239,000	74,136,000
Other amortization and depreciation, net	707,000	625,000
Stock-based compensation expense	593,000	629,000
Change in other assets and liabilities, net	642,000	(1,744,000)
Net cash and cash equivalents provided by operating activities	84,930,000	92,975,000
Investing activities:
Purchase of investments	(2,100,712,000)	(567,704,000)
Principal payments received on investments	195,061,000	95,452,000
Proceeds from sales of investments	432,552,000	525,973,000
Principal payments received on mortgage loans held for investment, net	1,199,000	2,101,000
Net (payments) receipts on derivatives, including terminations	(174,023,000)	54,050,000
Other investing activities	(1,348,000)	(68,000)
Net cash and cash equivalents (used in) provided by investing activities	(1,647,271,000)	109,804,000
Financing activities:
Borrowings under repurchase agreements	60,627,601,000	54,577,482,000
Repayments of repurchase agreement borrowings	(59,080,133,000)	(54,628,400,000)
Principal payments on non-recourse collateralized financing	(386,000)	(1,144,000)
Proceeds from issuance of preferred stock	13,188,000	494,000
Proceeds from issuance of common stock	63,751,000	5,914,000
Cash paid for stock issuance costs	(185,000)	0
Payments related to tax withholding for stock-based compensation	(296,000)	(364,000)
Dividends paid	(38,553,000)	(26,003,000)
Net cash and cash equivalents provided by (used in) financing activities	1,584,987,000	(72,021,000)
Net increase in cash, cash equivalents, and restricted cash	22,646,000	130,758,000
Cash, cash equivalents, and restricted cash at beginning of period	88,704,000	87,200,000
Cash, cash equivalents, and restricted cash at end of period	111,350,000	217,958,000
Supplemental Disclosure of Cash Activity:
Cash paid for interest	$ 51,650,000	$ 24,114,000