CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands		Total	Series C Preferred Stock	Series B Preferred Stock	Preferred Stock Series C Preferred Stock	Preferred Stock Series B Preferred Stock	Common Stock	Additional Paid-in Capital	Additional Paid-in Capital Series C Preferred Stock	Accumulated Deficit	Accumulated Deficit Series C Preferred Stock	Accumulated Deficit Series B Preferred Stock	Accumulated Other Comprehensive Income	Revision of Prior Period, Accounting Standards Update, Adjustment	Revision of Prior Period, Accounting Standards Update, Adjustment Accumulated Deficit
Increase (Decrease) in Stockholders' Equity
Preferred stock, liquidation preference (in dollars per share)						$ 25.00
Balance (in shares) at Dec. 31, 2017						8,000,000	397,831,000
Beginning balance at Dec. 31, 2017		$ 3,261,636				$ 80	$ 3,978	$ 3,227,304		$ (578,950)			$ 609,224	$ 295	$ 295
Increase (Decrease) in Stockholders' Equity
Net (loss)/income		301,801								301,801
Issuance of stock, net of expenses (in shares)							52,420,000
Issuance of stock, net of expenses		392,145					$ 520	391,625
Repurchase of shares of common stock (in shares)	[1]						(464,000)
Repurchase of shares of common stock	[1]	(3,392)						(3,392)
Equity based compensation expense		7,999						7,999
Change in accrued dividends attributable to stock-based awards		(261)						(261)
Dividends declared on common stock		(339,244)								(339,244)
Dividends declared on preferred stock		(15,000)								(15,000)
Dividends attributable to dividend equivalents		(942)								(942)
Change in unrealized losses on MBS, net		(203,481)											(203,481)
Derivative hedging instrument fair value changes and amortization, net		14,545											14,545
Changes in fair value of financing agreements at fair value due to changes in instrument-specific credit risk		0
Balance (in shares) at Dec. 31, 2018						8,000,000	449,787,000
Ending balance at Dec. 31, 2018		$ 3,416,101				$ 80	$ 4,498	3,623,275		(632,040)			420,288
Increase (Decrease) in Stockholders' Equity
Adjustments related to tax withholding for share-based compensation							$ 3,400
Shares paid for tax withholding for share based compensation (in shares)							464,429
Preferred stock, dividend rate						7.50%
Preferred stock, cash dividends declared (in dollars per share)				$ 1.875
Common stock, cash dividends declared (in dollars per share)		$ 0.80
Preferred stock, liquidation preference (in dollars per share)						$ 25.00
Net (loss)/income		$ 378,117								378,117
Issuance of stock, net of expenses (in shares)							3,145,000
Issuance of stock, net of expenses		12,325					$ 26	12,299
Repurchase of shares of common stock (in shares)	[1]						(563,000)
Repurchase of shares of common stock	[1]	(4,118)						(4,118)
Equity based compensation expense		9,230						9,230
Change in accrued dividends attributable to stock-based awards		(345)						(345)
Dividends declared on common stock		(361,033)								(361,033)
Dividends declared on preferred stock		(15,000)								(15,000)
Dividends attributable to dividend equivalents		(1,084)								(1,084)
Change in unrealized losses on MBS, net		(24,445)											(24,445)
Derivative hedging instrument fair value changes and amortization, net		(25,796)											(25,796)
Changes in fair value of financing agreements at fair value due to changes in instrument-specific credit risk		0
Balance (in shares) at Dec. 31, 2019					0	8,000,000	452,369,000
Ending balance at Dec. 31, 2019		$ 3,383,952			$ 0	$ 80	$ 4,524	3,640,341		(631,040)			370,047	$ (8,326)	$ (8,326)
Increase (Decrease) in Stockholders' Equity
Accounting Standards Update [Extensible List]		us-gaap:AccountingStandardsUpdate201613Member
Adjustments related to tax withholding for share-based compensation							$ 4,100
Shares paid for tax withholding for share based compensation (in shares)							562,815
Preferred stock, dividend rate				7.50%	6.50%	7.50%
Preferred stock, cash dividends declared (in dollars per share)				$ 1.875
Common stock, cash dividends declared (in dollars per share)		$ 0.80
Preferred stock, liquidation preference (in dollars per share)					$ 25.00	$ 25.00
Net (loss)/income		$ (679,390)								(679,390)
Issuance of stock, net of expenses (in shares)					11,000,000		13,792,000
Issuance of stock, net of expenses		7,453	$ 266,052		$ 110		$ 138	7,315	$ 265,942
Repurchase of shares of common stock (in shares)	[1]						(14,447,000)
Repurchase of shares of common stock	[1]	(53,577)					$ (145)	(53,432)
Equity based compensation expense		6,715						6,715
Change in accrued dividends attributable to stock-based awards		856						856
Dividends declared on common stock		(56,546)								(56,546)
Dividends declared on preferred stock		(29,796)	$ (14,796)	$ (15,000)							$ (14,796)	$ (15,000)
Dividends attributable to dividend equivalents		(229)								(229)
Change in unrealized losses on MBS, net		(313,115)											(313,115)
Derivative hedging instrument fair value changes and amortization, net		22,675											22,675
Warrants issued and repurchased, net		(19,608)
Changes in fair value of financing agreements at fair value due to changes in instrument-specific credit risk		(2,314)											(2,314)
Balance (in shares) at Dec. 31, 2020					11,000,000	8,000,000	451,714,000
Ending balance at Dec. 31, 2020		$ 2,524,802			$ 110	$ 80	$ 4,517	$ 3,848,129		$ (1,405,327)			$ 77,293
Increase (Decrease) in Stockholders' Equity
Adjustments related to tax withholding for share-based compensation							$ 2,700
Shares paid for tax withholding for share based compensation (in shares)							360,534
Preferred stock, dividend rate			6.50%	7.50%	6.50%	7.50%
Preferred stock, cash dividends declared (in dollars per share)			$ 1.345	$ 1.875
Common stock, cash dividends declared (in dollars per share)		$ 0.125
Preferred stock, liquidation preference (in dollars per share)					$ 25.00	$ 25.00

[1] For the year ended December 31, 2020, includes approximately $2.7 million (360,534 shares) surrendered for tax purposes related to equity-based compensation awards. For the year ended December 31, 2019, includes approximately $4.1 million (562,815 shares) surrendered for tax purposes related to equity-based compensation awards. For the year ended December 31, 2018, includes approximately $3.4 million (464,429 shares) surrendered for tax purposes related to equity-based compensation awards.