Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Assets [Abstract]
Cash	$ 456,957	$ 366,023
Cash collateral posted to counterparties	114,732	55,284
Mortgage-backed securities (including pledged of $3,119,668 and $3,011,319, respectively), at fair value	3,215,017	3,181,839
Mortgage loans held for investment, at fair value	3,757	4,268
Receivable for securities pending settlement	1,491	2,771
Derivative assets	34,183	7,969
Accrued interest receivable	15,914	14,184
Other assets, net	7,171	7,400
Total assets	3,849,222	3,639,738
Liabilities:
Repurchase agreements	2,952,802	2,849,916
Broker-Dealer, Payable to Other Broker-Dealer and Clearing Organization	48,046	0
Derivative liabilities	18,328	2,471
Cash collateral posted by counterparties	30,276	1,834
Accrued interest payable	1,524	1,365
Accrued dividends payable	6,672	6,541
Other liabilities	5,941	6,332
Total liabilities	3,063,589	2,868,459
Stockholders' Equity Attributable to Parent [Abstract]
Preferred stock, par value $0.01 per share; 50,000,000 shares authorized; 4,460,000 and 4,460,000 shares issued and outstanding, respectively ($111,500 and $111,500 aggregate liquidation preference, respectively)	107,843	107,843
Common stock, par value $0.01 per share, 90,000,000 shares authorized; 36,957,882 and 36,665,805 shares issued and outstanding, respectively	370	367
Additional paid-in capital	1,112,628	1,107,792
Accumulated other comprehensive (loss) income	(84,611)	6,729
Accumulated deficit	(350,597)	(451,452)
Total shareholders’ equity	785,633	771,279
Total liabilities and shareholders’ equity	$ 3,849,222	$ 3,639,738