Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Operating activities:
Net (loss) income	$ (41,722)	$ 117,209
Adjustments to reconcile net (loss) income to cash provided by operating activities:
Realized loss on sale of investments, net	23,315	0
Unrealized (gain) loss on investments, net	(57,120)	111,251
Loss (gain) on derivative instruments, net	67,267	(220,211)
Amortization of investment premiums, net	19,642	27,104
Other amortization and depreciation, net	585	566
Share-based compensation expense	1,010	846
Increase in accrued interest receivable	(1,974)	(1,730)
(Decrease) increase in accrued interest payable	(3,644)	159
Change in other assets and liabilities, net	(3,622)	(642)
Net cash provided by operating activities	3,737	34,552
Investing activities:
Purchases of investments	(310,352)	(349,839)
Principal payments received on trading securities	30,233	27,118
Principal payments received on available-for-sale investments	22,318	59,745
Principal payments received on mortgage loans held for investment	279	512
Net (payments) receipts on derivatives, including terminations	(101,425)	259,180
Increase in cash collateral posted by counterparties	26,690	28,442
Net cash (used in) provided by investing activities	(332,257)	25,158
Financing activities:
Borrowings under repurchase agreements	5,428,877	2,197,547
Repayments of repurchase agreement borrowings	(5,136,158)	(2,094,661)
Proceeds from issuance of common stock	2,771	4,245
Payments related to tax withholding for share-based compensation	(276)	(236)
Dividends paid	(22,949)	(16,223)
Net cash provided by financing activities	272,265	90,672
Net (decrease) increase in cash including cash posted to counterparties	(56,255)	150,382
Cash including cash posted to counterparties at beginning of period	449,877	421,307
Cash including cash posted to counterparties at end of period	393,622	571,689
Supplemental Disclosure of Cash Activity:
Cash paid for interest	$ 34,952	$ 1,589