Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Assets [Abstract]
Cash	$ 349,381	$ 295,602
Cash collateral posted to counterparties	85,342	14,758
Mortgage-backed securities (including pledged of $2,473,257 and $2,467,859, respectively), at fair value	2,995,502	2,596,255
Mortgage loans held for investment, at fair value	5,146	6,264
Receivable for sales pending settlement	1,057	150,432
Derivative assets	16,854	11,342
Accrued interest receivable	14,056	14,388
Other assets, net	6,957	6,394
Total assets	3,474,295	3,095,435
Liabilities:
Repurchase agreements	2,321,043	2,437,163
Payable for purchases pending settlement	350,854	5
Derivative liabilities	27,325	1,634
Derivative Asset, Collateral, Obligation to Return Cash, Offset	9,326	7,681
Accrued interest payable	405	1,410
Accrued dividends payable	6,086	5,814
Other liabilities	3,627	8,275
Total liabilities	2,718,666	2,461,982
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; 34,344,566 and 23,697,970 shares issued and outstanding, respectively	343	237
Additional paid-in capital	1,065,670	869,495
Accumulated other comprehensive income	29,375	80,261
Accumulated deficit	(447,602)	(491,104)
Total shareholders’ equity	755,629	633,453
Total liabilities and shareholders’ equity	$ 3,474,295	$ 3,095,435