Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Agency securities pledged	$ 11,188,502	$ 6,743,689
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	50,000,000	50,000,000
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	125,000,000	125,000,000
Common stock, shares issued (in shares)	58,877,000	43,702,000
Common stock, shares outstanding (in shares)	58,876,984	43,702,000
Series A Preferred Stock
Preferred stock, par value (in dollars per share)		$ 0.001
Preferred stock, shares issued (in shares)		2,181,000
Preferred stock, shares outstanding (in shares)	2,180,572	2,180,572
Preferred stock, aggregate liquidation preference		$ 54,514
Preferred stock, dividend rate	8.25%	8.25%
Series B Preferred Stock
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	17,970,000
Preferred stock, shares issued (in shares)	8,383,000	6,369,000
Preferred stock, shares outstanding (in shares)	8,383,000	6,369,000
Preferred stock, aggregate liquidation preference	$ 209,584	$ 159,232
Preferred stock, dividend rate	7.875%	7.875%
Credit Risk and Non-Agency Securities
Credit risk and non-agency securities pledged	$ 810,549	$ 698,255
U.S. Treasury Securities
Credit risk and non-agency securities pledged		$ 20,748