CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands		Total	Preferred Stock Series B Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income
Balance (in shares) at Dec. 31, 2014			8,000,000	370,084,000
Balance at Dec. 31, 2014		$ 3,203,272	$ 80	$ 3,701	$ 3,013,634	$ (568,596)	$ 754,453
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		313,226				313,226
Issuance of common stock, net of expenses (in shares)				809,000
Issuance of common stock, net of expenses (1)		1,221		$ 5	1,216
Repurchase of shares of common stock (in shares)	[1]			(309,000)
Repurchase of shares of common stock	[1]	(2,273)		$ 0	(2,273)
Equity based compensation expense		7,829			7,829
Accrued dividends attributable to stock-based awards		(450)			(450)
Dividends declared on common stock		(296,384)				(296,384)
Dividends declared on preferred stock		(15,000)				(15,000)
Dividends attributable to dividend equivalents		(1,041)				(1,041)
Change in unrealized gains/(losses) on MBS, net		(232,802)					(232,802)
Derivative hedging instrument fair value changes, net		(10,337)					(10,337)
Balance (in shares) at Dec. 31, 2015			8,000,000	370,584,000
Balance at Dec. 31, 2015		2,967,261	$ 80	$ 3,706	3,019,956	(572,332)	515,851
Increase (Decrease) in Stockholders' Equity
Cumulative effect adjustment on adoption of revised accounting standard for repurchase agreement financing		0					0
Net income		312,668				312,668
Issuance of common stock, net of expenses (in shares)				1,758,000
Issuance of common stock, net of expenses (1)		4,660		$ 13	4,647
Repurchase of shares of common stock (in shares)				(488,000)
Repurchase of shares of common stock		(3,551)			(3,551)
Equity based compensation expense		8,695			8,695
Accrued dividends attributable to stock-based awards		(685)			(685)
Dividends declared on common stock		(297,046)				(297,046)
Dividends declared on preferred stock		(15,000)				(15,000)
Dividends attributable to dividend equivalents		(931)				(931)
Change in unrealized gains/(losses) on MBS, net		35,153					35,153
Derivative hedging instrument fair value changes, net		22,678					22,678
Balance (in shares) at Dec. 31, 2016			8,000,000	371,854,000
Balance at Dec. 31, 2016		3,033,902	$ 80	$ 3,719	3,029,062	(572,641)	573,682
Increase (Decrease) in Stockholders' Equity
Cumulative effect adjustment on adoption of revised accounting standard for repurchase agreement financing		0					0
Net income		322,393				322,393
Issuance of common stock, net of expenses (in shares)				26,722,000
Issuance of common stock, net of expenses (1)		196,808		$ 259	196,549
Repurchase of shares of common stock (in shares)				(745,000)
Repurchase of shares of common stock		(5,995)			(5,995)
Equity based compensation expense		7,872			7,872
Accrued dividends attributable to stock-based awards		(184)			(184)
Dividends declared on common stock		(312,810)				(312,810)
Dividends declared on preferred stock		(15,000)				(15,000)
Dividends attributable to dividend equivalents		(892)				(892)
Change in unrealized gains/(losses) on MBS, net		245					245
Derivative hedging instrument fair value changes, net		35,297					35,297
Balance (in shares) at Dec. 31, 2017			8,000,000	397,831,000
Balance at Dec. 31, 2017		$ 3,261,636	$ 80	$ 3,978	$ 3,227,304	$ (578,950)	$ 609,224

[1] For the year ended December 31, 2017, includes approximately $6.0 million (744,588 shares) surrendered for tax purposes related to equity-based compensation awards. For the year ended December 31, 2016, includes approximately $3.6 million (487,559 shares) surrendered for tax purposes related to equity-based compensation awards. For the year ended December 31, 2015, includes approximately $2.3 million (309,206 shares) surrendered for tax purposes related to equity-based compensation awards.