CONSOLIDATED STATEMENT OF CHANGES IN STOCKHOLDERS' EQUITY (UNAUDITED) - USD ($) $ in Thousands		Total	Preferred Stock Series B 7.50% Cumulative Redeemable - Liquidation Preference $25.00 per Share		Common Stock		Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income
Balance at Dec. 31, 2013		$ 3,142,251	$ 80		$ 3,651		$ 2,972,369	$ (571,544)	$ 737,695
Balance (in shares) at Dec. 31, 2013			8,000,000		365,125,000
Increase (Decrease) in Stockholders' Equity
Cumulative effect adjustment on adoption of revised accounting standard for repurchase agreement financing		0
Net income		154,914						154,914	0
Issuance of common stock, net of expenses	[1]	16,846	$ 0		$ 24		16,822	0	0
Issuance of common stock, net of expenses (in shares)	[1]		0		2,414,000
Repurchase of shares of common stock	[1]	(241)	$ 0		$ 0		(241)	0	0
Repurchase of shares of common stock (in shares)	[1]		0		(64,000)
Equity based compensation expense		3,086					3,086	0	0
Accrued dividends attributable to stock-based awards		(109)					(109)	0	0
Dividends declared on common stock		(146,907)					0	(146,907)	0
Dividends declared on preferred stock		(7,500)					0	(7,500)	0
Dividends attributable to dividend equivalents		(384)					0	(384)	0
Change in unrealized gains on MBS, net		152,792					0	0	152,792
Change in unrealized losses on derivative hedging instruments, net		(39,454)					0	0	(39,454)
Balance at Jun. 30, 2014		3,275,294	$ 80		$ 3,675		2,991,927	(571,421)	851,033
Balance (in shares) at Jun. 30, 2014			8,000,000		367,475,000
Balance at Dec. 31, 2014		3,203,272	$ 80		$ 3,701		3,013,634	(568,596)	754,453
Balance (in shares) at Dec. 31, 2014			8,000,000		370,084,000
Increase (Decrease) in Stockholders' Equity
Cumulative effect adjustment on adoption of revised accounting standard for repurchase agreement financing		4,537						(4,537)	4,537
Net income		160,244						160,244	0
Issuance of common stock, net of expenses	[1]	623	$ 0		$ 1		622	0	0
Issuance of common stock, net of expenses (in shares)	[1]		0		134,000
Repurchase of shares of common stock	[1]	$ (238)	$ 0		$ 0		(238)	0	0
Repurchase of shares of common stock (in shares)		0	0	[1]	(22,000)	[1]
Equity based compensation expense		$ 2,569					2,569	0	0
Accrued dividends attributable to stock-based awards		(225)					(225)	0	0
Dividends declared on common stock		(148,153)					0	(148,153)	0
Dividends declared on preferred stock		(7,500)					0	(7,500)	0
Dividends attributable to dividend equivalents		(513)					0	(513)	0
Change in unrealized gains on MBS, net		(58,901)					0	0	(58,901)
Change in unrealized losses on derivative hedging instruments, net		(5,509)					0	0	(5,509)
Balance at Jun. 30, 2015		$ 3,145,669	$ 80		$ 3,702		$ 3,016,362	$ (569,055)	$ 694,580
Balance (in shares) at Jun. 30, 2015			8,000,000		370,196,000

[1] For the six months ended June 30, 2015 and 2014, includes approximately $169,000 (22,148 shares) and $480,000 (64,012 shares), respectively, surrendered for tax purposes related to equity-based compensation awards.