Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating activities:
Net income (loss)	$ 102,261	$ 177,530	$ (152,668)
Adjustments to reconcile net income (loss) to cash provided by operating activities:
Realized (gain) loss on sale of investments, net	(6,705)	(308,084)	5,755
Unrealized loss (gain) on investments, net	14,814	(20)	56
(Gain) loss on derivative instruments, net	(81,417)	172,290	186,949
Amortization of investment premiums, net	118,171	126,395	133,690
Other amortization and depreciation, net	2,308	1,989	1,684
Share-based compensation expense	2,516	1,823	1,205
Decrease (increase) in accrued interest receivable	204	11,821	(5,190)
(Decrease) increase in accrued interest payable	(45)	(14,175)	5,277
Change in other assets and liabilities, net	(5,137)	4,383	(1,412)
Net cash provided by operating activities	146,970	173,952	175,346
Investing activities:
Purchase of investments	(1,541,678)	(2,436,953)	(2,991,311)
Principal payments received on investments	430,856	474,731	537,481
Proceeds from sales of investments	472,943	4,491,873	1,033,066
Principal payments received on mortgage loans held for investment	2,101	2,854	2,103
Net receipts (payments) on derivatives, including terminations	86,247	(185,482)	(184,920)
(Decrease) increase in cash collateral posted by counterparties	(5,847)	5,681	(1,717)
Other investing activities	0	0	(121)
Net cash (used in) provided by investing activities	(555,378)	2,352,704	(1,605,419)
Financing activities:
Borrowings under repurchase agreements	12,635,222	31,054,242	102,505,318
Repayments of repurchase agreement borrowings	(12,222,469)	(33,369,427)	(101,020,954)
Principal payments on non-recourse collateralized financing	(118)	(2,646)	(738)
Proceeds from issuance of preferred stock	0	107,843	19,924
Proceeds from issuance of common stock	237,130	9,891	63,889
Cash paid for redemption of preferred stock	(69,708)	(100,000)	0
Cash paid for stock issuance costs	(329)	0	(185)
Cash paid for common stock repurchases	0	372	25,034
Payments related to tax withholding for share-based compensation	(853)	(245)	(296)
Dividends paid	(58,895)	(52,437)	(68,042)
Net cash provided by (used in) financing activities	519,980	(2,353,151)	1,473,882
Net increase in cash including cash posted to counterparties	111,572	173,505	43,809
Cash including cash posted to counterparties at beginning of period	309,735	136,230	92,421
Cash including cash posted to counterparties at end of period	421,307	309,735	136,230
Supplemental Disclosure of Cash Activity:
Cash paid for interest	$ 5,709	$ 46,054	$ 108,986