CONSOLIDATED BALANCE SHEETS (UNAUDITED) (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified			9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013 Cumulative Preferred Stock, Series A [Member]	Dec. 31, 2012 Cumulative Preferred Stock, Series A [Member]	Sep. 30, 2013 Convertible Preferred Stock [Member] Cumulative Convertible Preferred Stock, Series B [Member]	Dec. 31, 2012 Convertible Preferred Stock [Member] Cumulative Convertible Preferred Stock, Series B [Member]	Sep. 30, 2013 Redeemable Preferred Stock [Member] Cumulative Redeemable Preferred Stock, Series E [Member]	Dec. 31, 2012 Redeemable Preferred Stock [Member] Cumulative Redeemable Preferred Stock, Series E [Member]
Residential mortgage investments	$ 13,290,000	$ 13,450,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	250,000	250,000
Common stock, shares issued (in shares)	95,761	96,229
Common stock, shares outstanding (in shares)	95,761	96,229
Preferred stock, shares authorized (in shares)	100,000	100,000
Preferred stock, par value (in shares)	$ 0.10	$ 0.10
Preferred stock, shares issued (in shares)			0	186	0	16,493	6,800	0
Preferred stock, shares outstanding (in shares)			0	186	0	16,493	6,800	0
Preferred stock, dividend (in dollars per share)			$ 1.60	$ 1.60	$ 1.26	$ 1.26
Preferred stock, aggregate liquidation preference							$ 170,000
Preferred stock, dividend rate							7.50%