Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Operating activities:
Net (loss) income	$ (6,130)	$ 143,161	$ 102,261
Adjustments to reconcile net (loss) income to cash provided by operating activities:
Realized loss (gain) on sales of investments, net	74,916	89,067	(6,705)
Unrealized (gain) loss on investments, net	(142,501)	213,022	14,814
Loss (gain) on derivative instruments, net	32,905	(436,007)	(81,417)
Amortization of investment premiums, net	74,696	98,071	118,171
Other amortization and depreciation, net	2,315	2,354	2,308
Share-based compensation expense	4,833	4,419	2,516
(Increase) decrease in accrued interest receivable	(13,467)	(1,076)	204
Increase (decrease) in accrued interest payable	36,744	15,085	(45)
Change in other assets and liabilities, net	(2,111)	(1,744)	(5,137)
Net cash provided by operating activities	62,200	126,352	146,970
Investing activities:
Purchases of investments	(3,578,289)	(1,553,217)	(1,541,678)
Principal payments received on trading securities	233,387	123,982	36,515
Principal payments received on available-for-sale investments	86,272	225,639	394,341
Proceeds from sales of trading securities	348,091	588,651	0
Proceeds from Sale of Debt Securities, Available-for-sale	0	95,678	472,943
Principal payments received on mortgage loans held for investment	889	1,646	2,101
Net receipts on derivatives, including terminations	(95,968)	453,580	86,247
Decrease (increase) in cash collateral posted by counterparties	45,566	(1,399)	(5,847)
Net cash used in investing activities	(2,960,052)	(65,440)	(555,378)
Financing activities:
Borrowings under repurchase agreements	23,502,271	16,248,926	12,635,222
Repayments of repurchase agreement borrowings	(20,765,572)	(16,454,437)	(12,222,469)
Principal payments on non-recourse collateralized financing	0	0	(118)
Proceeds from issuance of common stock	42,626	246,882	237,130
Payments related to tax withholding for share-based compensation	(445)	(1,347)	(853)
Dividends paid	(93,041)	(72,366)	(58,895)
Net cash provided by (used in) financing activities	2,685,839	(32,342)	519,980
Net (decrease) increase in cash including cash posted to counterparties	(212,013)	28,570	111,572
Cash including cash posted to counterparties at beginning of period	449,877	421,307	309,735
Cash including cash posted to counterparties at end of period	237,864	449,877	421,307
Supplemental Disclosure of Cash Activity:
Cash paid for interest	178,705	28,527	5,709
Proceeds from (Repurchase of) Redeemable Preferred Stock	0	0	(69,708)
Cash paid for stock issuance costs	$ 0	$ 0	$ (329)