CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Residential whole loans, pledged as collateral	$ 427,880,000	$ 93,692,000
Residential whole loans, pledged as collateral, fair value	$ 734,331,000	$ 585,971,000
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	8,050,000	8,050,000
Preferred stock, dividend rate (as a percent)	7.50%	7.50%
Preferred stock, shares issued (in shares)	8,000,000	8,000,000
Preferred stock, shares outstanding (in shares)	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 (in shares)	886,950,000	886,950,000
Common stock, shares issued (in shares)	371,854,000	370,584,000
Common stock, shares outstanding (in shares)	371,854,000	370,584,000
Agency MBS
Mortgage backed securities pledged as collateral	$ 3,540,401,000	$ 4,532,094,000
Non-Agency MBS
Mortgage backed securities pledged as collateral	4,978,199,000	4,874,372,000
CRT securities
Mortgage backed securities pledged as collateral	$ 357,488,000	$ 170,352,000
Senior Notes
Stated interest rate	8.00%