Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Income Statement [Abstract]
Interest income, net of amortization of premium on Agency Securities		$ 91,703	$ 113,892	$ 191,253	$ 236,974
Interest expense		(13,917)	(14,979)	(28,108)	(29,726)
Interest expense- U.S. Treasury Securities sold short		0	4,263	0	4,263
Net Interest Income		77,786	94,650	163,145	202,985
Other Income (Loss):
Realized gain (loss) on sale of Agency Securities (reclassified from Other comprehensive income (loss))		(5,051)	11,167	1,493	81,036
Loss on short sale of U.S. Treasury Securities		0	(15,781)	0	(15,781)
Subtotal		(5,051)	(4,614)	1,493	65,255
Realized loss on derivatives	[1]	(59,978)	(34,498)	(51,880)	(46,236)
Unrealized gain (loss) on derivatives		194,507	(116,273)	(21,831)	(292,629)
Subtotal		134,529	(150,771)	(73,711)	(338,865)
Total Other Income (Loss)		129,478	(155,385)	(72,218)	(273,610)
Expenses:
Management fee		6,867	6,964	13,744	13,929
Professional fees		658	901	1,451	2,175
Insurance		172	186	342	369
Compensation		575	734	1,188	1,446
Other		974	670	1,653	1,424
Total Expenses		9,246	9,455	18,378	19,343
Net Income (Loss)		198,018	(70,190)	72,549	(89,968)
Dividends declared on preferred stock		(3,905)	(3,905)	(7,810)	(7,812)
Net Income (Loss) available (related) to common stockholders		$ 194,113	$ (74,095)	$ 64,739	$ (97,780)
Net income (loss) per share available (related) to common stockholders:
Basic (in usd per share)		$ 0.55	$ (0.21)	$ 0.18	$ (0.27)
Diluted (in usd per share)		0.55	(0.21)	0.18	(0.27)
Dividends declared per common share (in usd per share)		$ 0.12	$ 0.15	$ 0.24	$ 0.30
Weighted average common shares outstanding:
Basic (in shares)		351,332	357,111	352,134	357,302
Diluted (in shares)		352,175	357,111	352,977	357,302
Pro Forma for the effect of the pending 1 for 8 reverse stock split (See Note 1)
Pro forma, basic (in usd per share)		$ 4.40	$ (0.21)	$ 1.44	$ (0.27)
Pro forma, diluted (in usd per share)		4.40	(0.21)	1.44	(0.27)
Pro forma, dividends declared (in usd per share)		$ 0.96	$ 0.15	$ 1.92	$ 0.30
Pro forma, common shares outstanding, basic (in shares)		43,916	357,111	44,017	357,302
Pro forma, common shares outstanding, diluted (in shares)		44,022	357,111	44,122	357,302

[1] Interest expense related to our interest rate swap contracts is recorded as realized loss on derivatives on the condensed consolidated statements of operations. For additional information, see Note 8 to the condensed consolidated financial statements.