CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash Flows From Operating Activities:
Net income	$ 302,709	$ 306,839	$ 316,414
Adjustments to reconcile net income to net cash provided by operating activities:
Gain on sales of MBS and U.S. Treasury securities	(25,825)	(9,001)	(6,730)
Other-than-temporary impairment charges	0	1,200	10,570
Accretion of purchase discounts on MBS	(73,447)	(38,263)	(42,419)
Amortization of purchase premiums on MBS	58,207	52,298	38,466
Depreciation and amortization on real estate, fixed assets and other assets	5,831	3,534	2,664
Gain on sale of real estate	0	0	(430)
Equity-based compensation expense	4,158	6,488	4,385
Unrealized (gains)/losses on derivative instruments	(1,111)	(9,593)	14,855
(Increase)/decrease in interest receivable	8,180	(1,160)	(4,622)
(Increase)/decrease in prepaid and other assets	(5,549)	(12,767)	783
Realized loss on TBA short positions	7,517	0	0
Increase/(decrease) in accrued expenses and other liabilities, and excise tax and interest	3,610	3,820	(632)
Increase in accrued interest payable on financial instruments	13,808	6,992	1,105
Net cash provided by operating activities	298,088	310,387	334,409
Cash Flows From Investing Activities:
Principal payments on MBS	2,770,710	2,671,137	2,291,153
Proceeds from sale of MBS and U.S. Treasury securities	574,869	268,859	150,630
Purchases of MBS	(1,744,605)	(3,589,981)	(4,834,169)
Proceeds from sale of real estate	0	0	11,370
Additions to leasehold improvements, furniture, fixtures and real estate investment	(373)	(443)	(2,343)
Net cash provided by/(used in) investing activities	1,600,601	(650,428)	(2,383,359)
Cash Flows From Financing Activities:
Principal payments on repurchase agreements	(69,851,602)	(63,237,681)	(54,050,542)
Proceeds from borrowings under repurchase agreements	69,438,427	64,176,994	55,824,734
Proceeds from issuance of securitized debt	129,314	186,691	963,255
Principal payments on securitized debt	(409,606)	(415,395)	(308,668)
Payments made on obligation to return securities obtained as collateral	(246,850)	0	0
Maturity of obligation to return securities obtained as collateral	(275,402)	0	0
Payments made for resecuritization related costs	0	(1,814)	(6,981)
Proceeds from issuance of Senior Notes	0	100,000	0
Payments made for Senior Notes related costs	0	(3,415)	0
Cash disbursements on financial instruments underlying Linked Transactions	(419,802)	(585,393)	(2,327,609)
Cash received from financial instruments underlying Linked Transactions	405,436	462,889	1,710,520
Payments made for margin calls on repurchase agreements and interest rate swaps (“Swaps”)	(69,902)	(2,390)	(19,361)
Proceeds from reverse margin calls on repurchase agreements and Swaps	22,809	12,890	42,914
Payment made to purchase interest rate swaption (“Swaption”)	0	0	(915)
Settlement of TBA short positions	(7,517)	0	0
Proceeds from issuances of common stock	77,625	13,038	607,803
Payments made for redemption of Series A Preferred Stock	(96,000)	0	0
Proceeds from issuance of Series B Preferred Stock	200,000	0	0
Payments made for preferred stock offering costs	(6,684)	0	0
Payments made to repurchase common stock	(16,281)	(9,713)	0
Dividends paid on preferred stock	(13,750)	(8,160)	(8,160)
Dividends paid on common stock and DERs	(594,827)	(341,229)	(329,261)
Net cash (used in)/provided by financing activities	(1,734,612)	347,312	2,097,729
Net increase in cash and cash equivalents	164,077	7,271	48,779
Cash and cash equivalents at beginning of period	401,293	394,022	345,243
Cash and cash equivalents at end of period	565,370	401,293	394,022
Supplemental Disclosure of Cash Flow Information:
Interest paid	162,186	161,657	148,306
Non-cash investing and financing activities:
MBS recorded upon de-linking of Linked Transactions	0	175,194	773,046
Repurchase agreements recorded upon de-linking of Linked Transactions	0	0	46,698
Net increase in securities obtained as collateral/obligation to return securities obtained as collateral	401,135	202,432	306,401
Dividends and DERs declared and unpaid	$ 73,643	$ 72,222	$ 97,525