Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Operating activities:
Net income	$ 44,307	$ 9,051
Adjustments to reconcile net income to cash provided by operating activities:
Increase in accrued interest receivable	(3,094)	(2,453)
Increase (decrease) in accrued interest payable	1,389	(528)
Gain on derivative instruments, net	(38,354)	(175)
Loss on sale of investments, net	3,775	1,708
Fair value adjustments, net	(29)	(10)
Amortization of investment premiums, net	35,769	39,862
Other amortization and depreciation, net	312	325
Stock-based compensation expense	335	538
Change in other assets and liabilities, net	(2,514)	(1,210)
Net cash and cash equivalents provided by operating activities	41,896	47,108
Investing activities:
Purchase of investments	(321,348)	(141,436)
Principal payments received on investments	51,972	95,546
Proceeds from sales of investments	154,613	57,173
Principal payments received on mortgage loans held for investment, net	649	987
Net receipts on derivatives, including terminations	36,271	21,573
Other investing activities	(67)	(146)
Net cash and cash equivalents (used in) provided by investing activities	(77,910)	33,697
Financing activities:
Borrowings under repurchase agreements	27,508,732	21,748,733
Repayments of repurchase agreement borrowings	(27,460,742)	(21,821,740)
Principal payments on non-recourse collateralized financing	(234)	(370)
Proceeds from issuance of preferred stock	494	7,504
Proceeds from issuance of common stock	294	127
Cash paid for stock issuance costs	0	(36)
Payments related to tax withholding for stock-based compensation	(364)	(521)
Dividends paid	(12,982)	(12,626)
Net cash and cash equivalents provided by (used in) financing activities	35,198	(78,929)
Net (decrease) increase in cash, cash equivalents, and restricted cash	(816)	1,876
Cash, cash equivalents, and restricted cash at beginning of period	87,200	98,889
Cash, cash equivalents, and restricted cash at end of period	86,384	100,765
Supplemental Disclosure of Cash Activity:
Cash paid for interest	$ 10,251	$ 8,141