CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash Flows From Operating Activities:
Net income	$ 224,152	$ 237,620
Adjustments to reconcile net income to net cash provided by operating activities:
Gain on sales of MBS and U.S. Treasury securities	(19,678)	(7,232)
Other-than-temporary impairment charges	0	1,200
Accretion of purchase discounts on MBS	(48,322)	(28,173)
Amortization of purchase premiums on MBS	47,198	38,175
Depreciation and amortization on fixed assets and other assets	3,133	2,471
Equity-based compensation expense	2,946	4,374
Unrealized losses/(gains) on derivative instruments	(8,318)	8,851
Decrease/(increase) in interest receivable	6,193	(1,998)
Increase in prepaid and other assets	(5,146)	(10,342)
Increase in accrued expenses and other liabilities, and excise tax and interest	10,837	344
(Decrease)/increase in accrued interest payable on financial instruments	(2,503)	5,005
Net cash provided by operating activities	227,128	232,593
Cash Flows From Investing Activities:
Principal payments on MBS	2,231,495	1,977,366
Proceeds from sale of MBS and U.S. Treasury securities	493,613	137,079
Purchases of MBS	(1,532,982)	(2,896,359)
Additions to leasehold improvements, furniture and fixtures	(272)	(367)
Net cash provided by/(used in) investing activities	1,191,854	(782,281)
Cash Flows From Financing Activities:
Principal payments on repurchase agreements	(60,312,234)	(48,911,503)
Proceeds from borrowings under repurchase agreements	60,127,933	49,930,670
Proceeds from issuance of securitized debt	76,485	186,691
Principal payments on securitized debt	(303,608)	(312,740)
Payments made on obligation to return securities obtained as collateral	(200,050)	0
Maturity of obligation to return securities obtained as collateral	(275,402)	0
Payments made for resecuritization related costs	0	(1,814)
Proceeds from issuance of Senior Notes	0	100,000
Payments made for Senior Notes related costs	0	(3,415)
Cash disbursements on financial instruments underlying Linked Transactions	(254,155)	(513,418)
Cash received from financial instruments underlying Linked Transactions	243,325	390,363
Payments made for margin calls on repurchase agreements and interest rate swaps (“Swaps”)	(61,402)	(2,390)
Proceeds from reverse margin calls on repurchase agreements and Swaps	2,000	10,890
Proceeds from issuances of common stock	67,409	4,398
Payments made for redemption of Series A Preferred Stock	(96,000)	0
Proceeds from issuance of Series B Preferred Stock	200,000	0
Payments made for preferred stock offering costs	(6,684)	0
Payments made to repurchase common stock	(27)	0
Dividends paid on preferred stock	(10,000)	(6,120)
Dividends paid on common stock and DERs	(514,013)	(265,504)
Net cash (used in)/provided by financing activities	(1,316,423)	606,108
Net increase in cash and cash equivalents	102,559	56,420
Cash and cash equivalents at beginning of period	401,293	394,022
Cash and cash equivalents at end of period	503,852	450,442
Non-cash Investing and Financing Activities:
MBS recorded upon de-linking of Linked Transactions	0	174,940
Net increase in securities obtained as collateral/obligation to return securities obtained as collateral	221,578	203,303
Dividends and DERs declared and unpaid	$ 81,171	$ 76,051