CONSOLIDATED BALANCE SHEETS (UNAUDITED) (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2015	Jun. 30, 2015	Dec. 31, 2014
Assets
Residential mortgage investments	$ 13,630,000	$ 13,630,000	$ 13,480,000
Stockholders' equity
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	250,000	250,000	250,000
Common stock, shares issued (in shares)	95,790	95,790	95,848
Common stock, shares outstanding (in shares)	95,790	95,790	95,848
Preferred stock, par value (in dollars per share)	$ 0.10	$ 0.10	$ 0.10
Preferred stock, shares authorized (in shares)	100,000	100,000	100,000
Cumulative Redeemable Preferred Stock, Series E [Member]
Stockholders' equity
Preferred stock, dividend rate (in hundredths)	7.50%	7.50%
Redeemable Preferred Stock [Member] | Cumulative Redeemable Preferred Stock, Series E [Member]
Stockholders' equity
Preferred stock, dividend rate (in hundredths)		7.50%	7.50%
Preferred stock, shares issued (in shares)	8,086	8,086	7,618
Preferred stock, shares outstanding (in shares)	8,086	8,086	7,618
Preferred stock, aggregate liquidation preference	$ 202,146	$ 202,146	$ 190,454