Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Assets [Abstract]
Cash	$ 366,023	$ 295,602
Cash collateral posted to counterparties	55,284	14,133
Mortgage-backed securities (including pledged of $3,011,319 and $2,467,859, respectively), at fair value	3,181,839	2,596,255
Mortgage loans held for investment, at fair value	4,268	6,264
Receivable for securities pending settlement	2,771	150,432
Derivative assets	7,969	11,342
Accrued interest receivable	14,184	14,388
Other assets, net	7,400	6,394
Total assets	3,639,738	3,094,810
Liabilities:
Repurchase agreements	2,849,916	2,437,163
Derivative liabilities	2,471	1,009
Cash collateral posted by counterparties	1,834	7,681
Accrued interest payable	1,365	1,410
Accrued dividends payable	6,541	5,814
Other liabilities	6,332	8,280
Total liabilities	2,868,459	2,461,357
Stockholders' Equity Attributable to Parent [Abstract]
Preferred stock, par value $0.01 per share; 50,000,000 shares authorized; 4,460,000 and 7,248,330 shares issued and outstanding, respectively ($111,500 and $181,208 aggregate liquidation preference, respectively)	107,843	174,564
Common stock, par value $0.01 per share, 90,000,000 shares authorized; 36,665,805 and 23,697,970 shares issued and outstanding, respectively	367	237
Additional paid-in capital	1,107,792	869,495
Accumulated other comprehensive income	6,729	80,261
Accumulated deficit	(451,452)	(491,104)
Total shareholders’ equity	771,279	633,453
Total liabilities and shareholders’ equity	$ 3,639,738	$ 3,094,810