CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Residential whole loans, carrying value	$ 2,814,259,000	$ 1,645,372,000
Residential whole loans, fair value	777,087,000	738,638,000
MSR-Related Assets, pledged as collateral (in dollars)	$ 1,169,872,000	$ 611,807,000
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	8,050,000	8,050,000
Preferred stock, dividend rate (as a percent)	7.50%	7.50%
Preferred stock, shares issued	8,000,000	8,000,000
Preferred stock, shares outstanding	8,000,000	8,000,000
Preferred stock, aggregate liquidation preference (in dollars)	$ 200,000,000	$ 200,000,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	886,950,000	886,950,000
Common stock, shares issued	450,622,000	449,787,000
Common stock, shares outstanding	450,622,000	449,787,000
Collateral Pledged | Agency MBS
Securities, at fair value, pledged as collateral	$ 2,223,163,000	$ 2,575,331,000
Collateral Pledged | Non-Agency MBS
Securities, at fair value, pledged as collateral	2,705,825,000	3,248,900,000
Collateral Pledged | CRT securities
Securities, at fair value, pledged as collateral	$ 403,381,000	$ 480,315,000