Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Operating activities:
Net income (loss)	$ 88,203	$ 137,084
Unrealized Gain (Loss) on Derivatives and Commodity Contracts	(64,463)	196,156
Adjustments to reconcile net income to cash provided by operating activities:
Realized gain on sale of investments, net	(6,705)	(298,728)
Unrealized loss (gain) on investments, net	2,981	(154)
Amortization of investment premiums, net	90,082	96,018
Other amortization and depreciation, net	1,726	1,428
Share-based compensation expense	1,755	1,299
Decrease in accrued interest receivable	636	10,869
Decrease in accrued interest payable	(771)	(14,526)
Change in other assets and liabilities, net	(4,718)	530
Net cash provided by operating activities	108,726	129,976
Investing activities:
Purchase of investments	(1,054,928)	(2,436,953)
Principal payments received on investments	321,262	344,055
Proceeds from sales of investments	474,908	4,401,909
Principal payments received on mortgage loans held for investment	1,629	2,170
Net receipts (payments) on derivatives, including terminations	22,082	(197,932)
Increase (Decrease) Cash Collateral from Counterparties	14,951	342
Net cash (used in) provided by investing activities	(220,096)	2,113,591
Financing activities:
Borrowings under repurchase agreements	11,010,378	28,304,165
Repayments of repurchase agreement borrowings	(10,920,476)	(30,461,830)
Principal payments on non-recourse collateralized financing	(118)	(2,107)
Proceeds from issuance of preferred stock	0	107,988
Proceeds from issuance of common stock	224,350	0
Payments for Repurchase of Redeemable Preferred Stock	(69,708)	(100,000)
Cash paid for stock issuance costs	(329)	0
Payments for Repurchase of Common Stock	0	372
Payments related to tax withholding for share-based compensation	(853)	(245)
Dividends paid	(42,799)	(40,151)
Net cash provided by (used in) financing activities	200,445	(2,192,552)
Net increase in cash including cash posted to counterparties	89,075	51,015
Cash including cash posted to counterparties at beginning of period	310,360	136,230
Cash including cash posted to counterparties at end of period	399,435	187,245
Supplemental Disclosure of Cash Activity:
Cash paid for interest	$ 4,992	$ 44,216