MTGE Investment (MTGE) 10-Q 6 Nov 14 2014 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information Document	9 Months Ended
	Sep. 30, 2014	Nov. 01, 2014
Document and Entity Information [Abstract]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	30-Sep-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q3	'
Entity Registrant Name	'American Capital Mortgage Investment Corp.	'
Entity Central Index Key	'0001516973	'
Entity Filer Category	'Non-accelerated Filer	'
Current Fiscal Year End Date	'--12-31	'
Entity Common Stock, Shares Outstanding	'	51,142,063
Trading Symbol	'MTGE	'
Entity Well-known Seasoned Issuer	'Yes	'
Entity Voluntary Filers	'No	'
Entity Current Reporting Status	'Yes	'

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Assets:	'	'
Agency securities, at fair value (including pledged securities of $4,057,574 and $5,618,735, respectively)	$4,259,763	$5,641,682
Non-agency securities, at fair value (including pledged securities of $845,861 and $899,176, respectively)	1,075,867	1,011,217
Marketable Securities, Equity Securities	0	38,807
US Government Securities, at Carrying Value (including pledged securities of $460,333 and $571,145, respectively)	467,201	637,342
Cash and cash equivalents	204,938	206,398
Restricted cash	88,161	21,005
Interest receivable	14,523	20,620
Derivative assets, at fair value	32,948	108,221
Receivable for agency securities sold	49,131	608,646
Receivable under reverse repurchase agreements	745,443	22,736
Mortgage servicing rights	100,314	15,608
Other assets	45,638	65,583
Total assets	7,083,927	8,397,865
Liabilities:	'	'
Secured Debt, Repurchase Agreements	4,921,812	7,158,192
Payable for Agency and Non-Agency Securities Purchased	98,671	0
Derivative liabilities, at fair value	48,742	11,327
Dividend payable	34,359	33,381
Obligation to Return Securities Borrowed Under Reverse Repurchase Agreements, at Fair Value	742,642	22,530
Accounts payable and other accrued liabilities	45,424	69,715
Total liabilities	5,891,650	7,295,145
Stockholders' equity:	'	'
Preferred stock, $0.01 par value; 50,000 shares authorized, 2,200 and 0 shares issued and outstanding, respectively	53,039	0
Common stock, $0.01 par value; 300,000 shares authorized, 51,142 and 51,356 shares issued and outstanding, respectively	511	514
Additional paid-in capital	1,198,324	1,201,826
Retained earnings	-59,597	-99,620
Total stockholders' equity	1,192,277	1,102,720
Total liabilities and stockholders' equity	$7,083,927	$8,397,865

Consolidated_Balance_Sheets_Co

Consolidated Balance Sheets Consolidated Balance Sheets (Parenthetical) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Treasury securities pledged as collateral	$460,333	$571,145
Preferred Stock, Par or Stated Value Per Share	$22	$0
Preferred Stock, Shares Authorized	50,000	50,000
Preferred Stock, Shares Issued	2,200	0
Preferred Stock, Shares Outstanding	2,200	0
Common Stock, Par or Stated Value Per Share	$511	$561
Common Stock, Shares Authorized	300,000	300,000
Common Stock, Shares, Issued	51,142	56,071
Common Stock, Shares, Outstanding	51,142	56,071
Agency Securities [Member]	'	'
Security Owned and Pledged as Collateral, Fair Value	4,057,574	5,618,735
Agency Securities [Member] | Repurchase Agreements [Member]	'	'
Security Owned and Pledged as Collateral, Fair Value	4,056,943	5,618,735
Non-Agency Securities [Member] | Repurchase Agreements [Member]	'	'
Security Owned and Pledged as Collateral, Fair Value	$845,861	$899,176

Consolidated_Statement_Of_Oper

Consolidated Statement Of Operations (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Interest income:	'	'	'	'
Agency securities	$27,208	$54,587	$92,939	$145,823
Non-agency securities	16,324	15,847	47,794	39,871
Investment Income, Interest	114	77	247	311
Interest expense	-6,407	-10,949	-21,808	-28,098
Net interest income	37,239	59,562	119,172	157,907
Servicing:	'	'	'	'
Other operating income	13,081	0	34,034	0
Other noninterest expense	-16,213	0	-44,861	0
Net servicing operating loss	-3,132	0	-10,827	0
Other gains (losses):	'	'	'	'
Realized gain on agency securities, net	685	-71,179	-8,396	-83,484
Realized gain on non-agency securities, net	17,403	5,884	31,795	15,610
Realized loss on periodic settlements of interest rate swaps, net	-5,226	-14,449	-15,400	-32,228
Realized gain on other derivatives and securities, net	13,704	65,258	3,236	86,675
Unrealized gain on agency securities, net	-18,446	80,894	127,447	-290,810
Unrealized gain on non-agency securities, net	-21,103	-424	-11,255	6,303
Unrealized loss on other derivatives and securities, net	3,303	105,138	71,608	-92,918
Unrealized gain (loss) mortgage servicing rights	-3,076	0	-3,705	0
Total other gains, net	-19,362	-39,154	52,114	-205,016
Expenses:	'	'	'	'
Asset Management Costs	4,544	4,725	13,169	14,248
General and administrative expenses	1,908	1,781	5,584	5,486
Total expenses	6,452	6,506	18,753	19,734
Income before excise tax	8,293	13,902	141,706	-66,843
Excise tax	0	200	356	377
Net income	8,293	13,702	141,350	-67,220
Preferred Stock Dividends, Income Statement Impact	-1,117	0	-1,601	0
Net Income (Loss) Available to Common Stockholders, Basic	$7,176	$13,702	$139,749	($67,220)
Net income per common sharebbasic and diluted	$0.14	$0.25	$2.73	($1.26)
Weighted Average Number of Shares Outstanding, Basic and Diluted	51,142	54,515	51,185	53,348
Common Stock, Dividends, Per Share, Declared	$0.65	$0.70	$1.95	$2.40

Consolidated_Statement_of_Stoc

Consolidated Statement of Stockholders' Equity (USD $)	Total	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings (Accumulated Deficit) [Member]
In Thousands
Beginning Balance, Date Operations Commenced at Dec. 31, 2012	$925,562	$0	$360	$772,008	$153,194
Balance, Common Stock, shares at Dec. 31, 2012	'	'	35,964	'	'
Preferred Stock, Shares Outstanding at Dec. 31, 2012	'	0	'	'	'
Net income	-67,220	'	'	'	'
Issuance of common stock, shares	'	'	23,000	'	'
Issuance of common stock, value	583,915	'	230	583,685	'
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures	0	'	8	'	'
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures	'	'	0	'	'
Stock Repurchased During Period, Shares	'	'	-6,070	'	'
Stock Repurchased During Period, Value	'	'	-61	'	'
Stock Repurchased and Retired During Period, Value	-124,057	'	'	-123,996	'
Stock-based compensation	100	'	'	100	'
Common dividends declared	134,963	'	'	'	134,963
Balance at Sep. 30, 2013	'	'	'	'	'
Beginning Balance, Date Operations Commenced at Dec. 31, 2013	1,102,720	0	514	1,201,826	-99,620
Balance, Common Stock, shares at Dec. 31, 2013	56,071	'	51,356	'	'
Preferred Stock, Shares Outstanding at Dec. 31, 2013	0	0	'	'	'
Net income	141,350	'	'	'	'
Preferred Stock, Shares Issued	2,200	'	'	'	'
Issuance of common stock, shares	'	2,200	'	'	'
Issuance of common stock, value	53,039	53,039	'	'	'
Stock Repurchased During Period, Shares	200	'	-214	'	'
Stock Repurchased During Period, Value	4,200	'	-3	'	'
Stock Repurchased and Retired During Period, Value	-4,208	'	'	-4,205	'
Stock-based compensation	703	'	'	703	'
Dividends, Preferred Stock, Cash	-1,601	'	'	'	-1,601
Common dividends declared	99,726	'	'	'	99,726
Balance at Sep. 30, 2014	$1,192,277	$53,039	$511	$1,198,324	($59,597)
Preferred Stock, Shares Outstanding at Sep. 30, 2014	2,200	2,200	'	'	'
Balance, Common Stock, shares at Sep. 30, 2014	51,142	'	51,142	'	'

Consolidated_Statement_Of_Cash

Consolidated Statement Of Cash Flows (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
CASH FLOWS FROM (USED IN) OPERATING ACTIVITIES:	'	'
Net income (loss)	$141,350	($67,220)
Adjustments to reconcile net income to net cash used in operating activities:	'	'
Investment Income, Amortization of Premium	26,586	31,141
Accretion of Discount	-30,486	-25,390
Amortization of Mortgage Servicing Rights (MSRs)	2,830	0
Unrealized loss (gain) on securities and derivatives, net	-40,879	191,589
Realized loss (gain) on agency securities, net	8,396	83,484
Realized gain on non-agency securities, net	-31,795	-15,610
Realized loss (gain) on derivatives and securities, net	14,004	-54,447
Stock-based compensation	703	100
Increase in interest receivable	6,097	-8,659
Increase in other assets	20,119	-2,305
Increase in accounts payable and other accrued liabilities	-855	47,434
Net cash from (used in) operating activities	116,070	180,117
CASH FLOWS FROM (USED IN) INVESTING ACTIVITIES:	'	'
Purchases of agency securities	-343,694	-8,316,225
Purchases of non-agency securities	-571,871	-438,726
Servicing Asset at Fair Value, Additions	-87,820	0
Proceeds from sale of agency securities	2,067,118	5,356,680
Proceeds from sale of non-agency securities	461,415	160,405
Principal collections on agency securities	418,891	507,922
Proceeds From Principal Collection Of Non Agency Mortgag eBacked Securities	87,087	79,113
Payments for Securities Purchased under Agreements to Resell	-722,707	418,888
Purchase Of US Treasury Securities	-1,909,460	-7,208,703
Proceeds from sale of U.S. Treasury securities	2,806,869	5,982,222
Proceeds from terminations of interest rate swaptions	17,525	42,638
Payment of premiums for interest rate swaptions	-1,552	-46,362
Increase (Decrease) in Restricted Cash	-67,156	-8,232
Payments for (Proceeds from) Other Investing Activities	15,896	4,965
Net cash flows from (used in) investing activities	2,170,541	-3,465,415
CASH FLOWS FROM (USED IN) FINANCING ACTIVITIES:	'	'
Payments of Dividends	-100,522	-130,300
Proceeds from Issuance of Preferred Stock and Preference Stock	53,039	0
Proceeds from common stock offerings, net of offering costs	0	583,915
Payments for Repurchase of Common Stock	-4,208	-124,057
Proceeds from repurchase agreements	26,437,702	61,974,922
Repayments of Short-term Debt	-28,674,082	-58,972,367
Net cash flow from (used in) financing activities	-2,288,071	3,332,113
Net increase (decrease) in cash and cash equivalents	-1,460	46,815
Cash and cash equivalents at beginning of period	206,398	157,314
Cash and cash equivalents at end of period	$204,938	'

Unaudited_Interim_Consolidated

Unaudited Interim Consolidated Financial Statements (Notes)	9 Months Ended
	Sep. 30, 2014
Unaudited Interim Consolidated Financial Statements [Abstract]	'
Unaudited Interim Consolidated Financial Statements [Text Block]	'
	Unaudited Interim Consolidated Financial Statements
	The unaudited interim consolidated financial statements of American Capital Mortgage Investment Corp. (referred to throughout this report as the "Company", "we", "us" and "our") are prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and pursuant to the requirements for reporting on Form 10-Q and Article 10 of Regulation S-X. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of income and expenses during the reporting period. Actual results could differ from those estimates.
	Our unaudited interim consolidated financial statements include the accounts of our wholly-owned subsidiaries, American Capital Mortgage Investment TRS, LLC and American Capital Mortgage 2013, LLC and, in turn, its wholly-owned subsidiary Residential Credit Solutions, Inc. ("RCS"). Significant intercompany accounts and transactions have been eliminated. In the opinion of management, all adjustments, consisting solely of normal recurring accruals, necessary for the fair presentation of financial statements for the interim period have been included. The current period’s results of operations are not necessarily indicative of results that ultimately may be achieved for the year.

Organization_Notes

Organization (Notes)	9 Months Ended
	Sep. 30, 2014
Organization [Abstract]	'
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]	'
	Organization
	We were incorporated in Maryland on March 15, 2011 and commenced operations on August 9, 2011 following the completion of our initial public offering ("IPO"). We are externally managed by American Capital MTGE Management, LLC (our "Manager"), an affiliate of American Capital, Ltd. ("American Capital"). Our common stock is traded on the NASDAQ Global Select Market under the symbol "MTGE."
	We invest in, finance and manage a leveraged portfolio of mortgage-related investments, which we define to include agency residential mortgage-backed securities ("RMBS"), non-agency mortgage investments and other mortgage-related investments. Agency RMBS include residential mortgage pass-through certificates and collateralized mortgage obligations ("CMOs") structured from residential mortgage pass-through certificates for which the principal and interest payments are guaranteed by a government-sponsored enterprise ("GSE"), such as Federal National Mortgage Association ("Fannie Mae") and Federal Home Loan Mortgage Corporation ("Freddie Mac"), or by a U.S. Government agency, such as Government National Mortgage Association ("Ginnie Mae"). Non-agency mortgage investments include RMBS backed by residential mortgages that are not guaranteed by a GSE or U.S. Government agency. Non-agency mortgage investments may also include prime and non-prime residential mortgage loans. Other mortgage-related investments may include mortgage servicing rights ("MSR"), GSE credit risk transfer securities, commercial mortgage-backed securities ("CMBS"), commercial mortgage loans and mortgage-related derivatives.
	Our objective is to provide attractive risk-adjusted returns to our stockholders over the long-term through a combination of dividends and net book value appreciation. In pursuing this objective, we rely on our Manager’s expertise to construct and manage a diversified mortgage investment portfolio by identifying asset classes that, when properly financed and hedged, are designed to produce attractive returns across a variety of market conditions and economic cycles, considering the risks associated with owning such investments.
	We have elected to be taxed as a REIT under the Internal Revenue Code of 1986, as amended (the "Internal Revenue Code"). As such, we are required to distribute annually at least 90% of our taxable net income. As long as we continue to qualify as a REIT, we will generally not be subject to U.S. Federal or state corporate taxes on our taxable net income to the extent that we distribute all of our annual taxable net income to our stockholders. It is our intention to distribute 100% of our taxable net income, after application of available tax attributes, within the time limits prescribed by the Internal Revenue Code, which may extend into the subsequent taxable year.
	On November 27, 2013, our wholly-owned subsidiary, American Capital Mortgage 2013, LLC acquired RCS, a fully-licensed mortgage servicer based in Fort Worth, Texas that has approvals from Fannie Mae, Freddie Mac, and Ginnie Mae to hold and manage MSR and residential mortgage loans. See Note 11 - Other Assets for additional information.

Summary_of_Significant_Account

Summary of Significant Accounting Policies (Notes)	9 Months Ended
	Sep. 30, 2014
Summary of Significant Accounting Policies [Abstract]	'
Summary of Significant Accounting Policies	'
	Summary of Significant Accounting Policies
	Fair Value of Financial Assets
	We have elected the option to account for all of our financial assets, including all mortgage-related investments, at estimated fair value, with changes in fair value reflected in income during the period in which they occur. In management's view, this election more appropriately reflects the results of our operations for a particular reporting period, as financial asset fair value changes are presented in a manner consistent with the presentation and timing of the fair value changes of hedging instruments. See Note 9 - Fair Value Measurements.
	Interest Income
	Interest income is accrued based on the outstanding principal amount of the securities and their contractual terms. Premiums or discounts associated with the purchase of agency RMBS and non-agency RMBS of high credit quality are amortized or accreted into interest income, respectively, over the projected lives of the securities, including contractual payments and estimated prepayments, using the effective interest method.
	We estimate long-term prepayment speeds using a third-party service and market data. The third-party service estimates prepayment speeds for our securities using models that incorporate the mortgage rates, age, size and loan-to-value ratios of the outstanding underlying loans, as well as current mortgage rates, forward yield curves, volatility and other factors. We review the prepayment speeds estimated by the third-party service and compare the results to market consensus prepayment speeds, if available. We also consider historical prepayment speeds and current market conditions to validate the reasonableness of the prepayment speeds estimated by the third-party service, and based on our Manager’s judgment, we may make adjustments to its estimates. Actual and anticipated prepayment experience is reviewed at least quarterly and effective yields are recalculated when differences arise between the previously estimated future prepayments and the amounts actually received plus currently anticipated future prepayments. If the actual and anticipated future prepayment experience differs from our prior estimate of prepayments, we are required to record an adjustment in the current period to the amortization or accretion of premiums and discounts for the cumulative difference in the effective yield through the reporting date.
	At the time we purchase non-agency RMBS and loans that are not of high credit quality, we determine an effective yield based on our estimate of the timing and amount of future cash flows and our cost basis. Our initial cash flow estimates for these investments are based on our observations of current information and events and include assumptions related to interest rates, prepayment rates and the impact of default and severity rates on the timing and amount of credit losses. On at least a quarterly basis, we review the estimated cash flows and make appropriate adjustments, based on input and analysis received from external sources, internal models, and our judgment about interest rates, prepayment rates, the timing and amount of credit losses, and other factors. Any resulting changes in effective yield are recognized prospectively based on the current amortized cost of the investment as adjusted for credit impairment, if any.
	Mortgage Servicing Rights, at Fair Value
	Our MSR represent the right to service mortgage loans for a servicing fee. MSR are reported at fair value on our consolidated balance sheets, with changes in fair value related to changes in valuation inputs and assumptions reported as unrealized loss on MSR on the consolidated statements of operations. Servicing fees, incentive fees and ancillary income are reported within servicing income on the consolidated statements of operations. The related servicing expenses and realization of cash flows related to underlying loan repayments, net of recoveries of contractual prepayment protection, are recorded in servicing expenses on the consolidated statements of operations. See Note 10 - Mortgage Servicing Rights for further discussion on MSR.
	The accounting model used to evaluate whether a transfer of MSR qualifies as a sale is based on a risks and rewards approach, as MSR are not financial assets. In certain cases where we transfer the economics of MSR while retaining the actual servicing function, we retain the risk associated with servicing and, as a result, the transfer does not qualify for sale accounting. As such, we retain the MSR, together with an offsetting financing liability on our consolidated balance sheets. We have elected the option to account for MSR financing liabilities at estimated fair value, with changes in fair value reflected in income during the period in which they occur. See Note 12 - Accounts Payable and Other Accrued Liabilities for the presentations of our mortgage servicing liability.
	We may be obligated to fund advances of principal and interest payments due to third party owners of the loans but not yet received from the individual borrowers. We may also be obligated to fund advances of real estate taxes and insurance, protective advances to preserve the value of the underlying property, and expenses associated with remedial action in respect of defaulted loans. These servicing advances are reported within other assets on the consolidated balance sheets.
	REIT Equity Securities, at Fair Value
	REIT equity securities represent investments in the common stock of other publicly traded mortgage REITs that invest predominately in agency RMBS. We designate our investments in REIT equity securities as trading securities and report them at fair value on the accompanying consolidated balance sheets with changes in fair value recorded in unrealized gain (loss) on other derivatives and securities, net on the accompanying consolidated statements of operations. Dividend income from REIT equity securities is recorded in realized gain on other derivatives and securities, net.
	Repurchase Agreements
	We finance the acquisition of agency RMBS and certain non-agency RMBS for our investment portfolio through repurchase transactions under master repurchase agreements. We account for repurchase transactions as collateralized financing transactions which are carried at their contractual amounts, including accrued interest, as specified in the respective transaction agreements. The contractual amounts approximate fair value due to their short-term nature.
	Reverse Repurchase Agreements and Obligation to Return Securities Borrowed under Reverse Repurchase Agreements
	From time to time we borrow securities to cover short sales of U.S. Treasury securities through reverse repurchase transactions under our master repurchase agreements (see Derivatives below). We account for these as securities borrowing transactions and recognize an obligation to return the borrowed securities at fair value on the consolidated balance sheets based on the value of the underlying borrowed securities as of the reporting date. Our reverse repurchase agreements generally mature daily. The fair value of our reverse repurchase agreements is assumed to equal cost as the interest rates are reset daily.
	Derivatives
	We utilize a risk management strategy, under which we may use a variety of derivative instruments to hedge some of our exposure to market risks, including interest rate risk, prepayment risk, extension risk and credit risk. The objective of our risk management strategy is to reduce fluctuations in net book value over a range of market conditions. The principal instruments that we currently use are interest rate swaps and options to enter into interest rate swaps ("interest rate swaptions"). We also utilize forward contracts for the purchase or sale of agency RMBS, or to-be-announced forward ("TBA") contracts, and short sales of U.S. Treasury securities and U.S. Treasury futures contracts. We may also purchase or write put or call options on TBA securities and we may invest in other types of mortgage derivatives, such as synthetic total return swaps.
	We also enter into TBA contracts as a means of investing in and financing agency RMBS (thereby increasing our "at
	risk" leverage) or as a means of disposing of or reducing our exposure to agency RMBS (thereby reducing our "at risk" leverage). Pursuant to TBA contracts, we agree to purchase or sell, for future delivery, agency RMBS with certain principal and interest terms and certain types of collateral, but the particular agency RMBS to be delivered are not identified until shortly before the TBA settlement date. We may also choose, prior to settlement, to move the settlement of these securities out to a later date by entering into an offsetting short or long position (referred to as a "pair off"), net settling the paired off positions for cash, and simultaneously purchasing or selling a similar TBA contract for a later settlement date. This transaction is commonly referred to as a "dollar roll." The agency RMBS purchased or sold for a forward settlement date are typically priced at a discount to agency RMBS for settlement in the current month. This difference (or discount) is referred to as the "price drop." The price drop is the economic equivalent of net interest carry income on the underlying agency RMBS over the roll period (interest income less implied financing cost) and is commonly referred to as "dollar roll income (loss)." Consequently, forward purchases of agency RMBS and dollar roll transactions represent a form of off-balance sheet financing.
	We recognize all derivative instruments as either assets or liabilities on the balance sheets, measured at fair value. As we have not designated any derivatives as hedging instruments, all changes in fair value are reported in earnings in our consolidated statements of operations in unrealized gain (loss) on other derivatives and securities, net during the period in which they occur. Derivatives in a gain position are reported as derivative assets at fair value and derivatives in a loss position are reported as derivative liabilities at fair value in our consolidated balance sheets. Cash receipts and payments related to derivative instruments are classified in our consolidated statements of cash flows according to the underlying nature or purpose of the derivative transaction, generally in the investing section.
	Our derivative agreements generally contain provisions that allow for netting or setting off derivative assets and liabilities with each counterparty; however, we report related assets and liabilities on a gross basis in our consolidated balance sheets.
	The use of derivatives creates exposure to credit risk relating to potential losses that could be recognized in the event that the counterparties to these instruments fail to perform their obligations under the contracts. We attempt to minimize this risk by limiting our counterparties to major financial institutions with acceptable credit ratings, monitoring positions with individual counterparties and adjusting posted collateral as required.
	Interest rate swap agreements
	We use interest rate swaps to hedge the variable cash flows associated with short-term borrowings made under our repurchase agreement facilities. Under our interest rate swap agreements, we typically pay a fixed rate and receive a floating rate based on one, three or six-month LIBOR ("payer swaps") with terms up to 15 years. The floating rate we receive under our swap agreements has the effect of offsetting the repricing characteristics of our repurchase agreements and cash flows on such liabilities. Our swap agreements are privately negotiated in the over-the-counter ("OTC") market and may be centrally cleared through a registered commodities exchange ("centrally cleared swaps").
	We estimate the fair value of our centrally cleared interest rate swaps using the daily settlement price determined by the respective exchange. Centrally cleared swaps are valued by the exchange using a pricing model that references the underlying rates, including the overnight index swap rate and LIBOR forward rate, to produce the daily settlement price. We estimate the fair value of our "non-centrally cleared" swaps using a combination of inputs from counterparty and third-party pricing models to estimate the net present value of the future cash flows using a forward yield curve in effect as of the end of the measurement period. We also incorporate any of our own and our counterparties’ unmitigated nonperformance risk in estimating the fair value of our interest rate swaps. In considering the effect of nonperformance risk, we consider the impact of netting and credit enhancements, such as collateral postings and guarantees, and have concluded that our own and our counterparty credit risk is not significant to the overall valuation of these agreements.
	The payment of periodic settlements of net interest on interest rate swaps is reported in realized loss on periodic settlements of interest rate swaps, net in our consolidated statements of operations. Cash payments received or paid for the early termination of an interest rate swap agreement are recorded as realized gain on other derivatives and securities, net in our consolidated statements of operations. Changes in fair value of our interest rate swap agreements are reported in unrealized gain (loss) on other derivatives and securities, net in our consolidated statements of operations.
	Interest rate swaptions
	We purchase interest rate swaptions to help mitigate the potential impact of larger increases or decreases in interest rates
	on the performance of our investment portfolio. The interest rate swaptions provide us the option to enter into an interest rate swap agreement for a predetermined notional amount, stated term and pay or receive interest rates in the future. The premium paid for interest rate swaptions is reported as a derivative asset in our consolidated balance sheets. We estimate the fair value of interest rate swaptions based on the fair value of the future interest rate swap that we have the option to enter into as well as the remaining length of time that we have to exercise the option. The difference between the premium and the fair value of the swaption is reported in unrealized gain (loss) on other derivatives and securities, net in our consolidated statements of operations. If a swaption expires unexercised, the realized loss on the swaption would be equal to the premium paid and reported in realized gain on other derivatives and securities, net in our consolidated statements of operations. If we exercise a swaption, the realized gain or loss on the swaption would be equal to the difference between the fair value of the underlying interest rate swap and the premium paid and reported in realized gain on other derivatives and securities, net in our consolidated statements of operations.
	Interest rate swaption agreements are privately negotiated in the OTC market and are not subject to central clearing. We estimate the fair value of interest rate swaptions using a combination of inputs from counterparty and third-party pricing models based on the fair value of the future interest rate swap that we have the option to enter into as well as the remaining length of time that we have to exercise the option, adjusted for non-performance risk, if any.
	TBA securities
	A TBA security is a forward contract for the purchase ("long position") or sale ("short position") of agency RMBS at a predetermined price, face amount, issuer, coupon and stated maturity on an agreed-upon future date. The specific agency RMBS delivered into the contract upon the settlement date, published each month by the Securities Industry and Financial Markets Association, are not known at the time of the transaction. We may enter into TBA contracts as a means of hedging against short-term changes in interest rates. We may also enter into TBA contracts as a means of acquiring or disposing of agency RMBS and we may from time to time utilize TBA dollar roll transactions to finance agency RMBS purchases.
	We account for all TBA contracts as derivatives since we cannot assert that it is probable at the inception and throughout the term of the contract that it will not settle net and will result in physical delivery of an agency security when it is issued. A TBA dollar roll transaction is a series of derivative transactions. The net settlement of a TBA contract is reported as realized gain on other derivatives and securities, net and changes in the fair value of our TBA contracts are reported as unrealized gain (loss) on other derivatives and securities, net in our consolidated statements of operations.
	We estimate the fair value of TBA securities based on similar methods used to value our agency RMBS.
	Forward commitments to purchase or sell specified securities
	We may enter into a forward commitment to purchase or sell specified securities as a means of acquiring assets or as a hedge against short-term changes in interest rates. Such forward commitments usually require physical settlement. Contracts for the purchase or sale of specified securities are accounted for as derivatives if the delivery of the specified agency RMBS and settlement extends beyond established market conventions. Realized gains and losses associated with forward commitments are recognized in realized gain on other derivatives and securities, net and unrealized gains and losses are recognized in unrealized gain (loss) on other derivatives and securities, net on our consolidated statements of operations.
	We estimate the fair value of forward commitments to purchase or sell specified RMBS based on methods used to value our RMBS, as well as the remaining length of time of the forward commitment.
	U.S. Treasury securities
	We purchase or sell short U.S. Treasury securities and U.S. Treasury futures contracts to help mitigate the potential impact of changes in interest rates on the performance of our portfolio. Realized gains and losses associated with purchases and short sales of U.S. Treasury securities and U.S. Treasury futures contracts are recognized in realized gain on other derivatives and securities, net, and unrealized gains and losses are recognized in unrealized gain (loss) on other derivatives and securities, net on our consolidated statements of operations.

Agency_Securities

Agency Securities	9 Months Ended
	Sep. 30, 2014
Agency Securities [Abstract]	'
Agency Securities	'
	Agency Securities
	The following tables summarize our investments in agency RMBS as of September 30, 2014 and December 31, 2013 (dollars in thousands):
		September 30, 2014
		Fannie Mae				Freddie Mac				Ginnie Mae				Total
	Agency RMBS:
	Par value	$	3,356,063			$	772,754			$	—			$	4,128,817
	Unamortized premium	143,203				38,808				—				182,011
	Amortized cost	3,499,266				811,562				—				4,310,828
	Gross unrealized gains	12,351				3,715				—				16,066
	Gross unrealized losses	(54,226		)		(12,905		)		—				(67,131		)
	Agency RMBS, at fair value	$	3,457,391			$	802,372			$	—			$	4,259,763
	Weighted average coupon as of September 30, 2014	3.37		%		3.5		%		—		%		3.39		%
	Weighted average yield as of September 30, 2014	2.56		%		2.69		%		—		%		2.59		%
	Weighted average yield for the three months ended September 30, 2014	2.49		%		2.61		%		—		%		2.52		%
	Weighted average yield for the nine months ended September 30, 2014	2.5		%		2.61		%		2.12		%		2.52		%
			September 30, 2014
			Amortized Cost				Gross Unrealized Gain				Gross Unrealized Loss				Fair Value
	Agency RMBS:
	Fixed rate		$	4,185,822			$	13,567			$	(67,131	)		$	4,132,258
	Adjustable rate		125,006				2,499				—				127,505
	Total		$	4,310,828			$	16,066			$	(67,131	)		$	4,259,763
		31-Dec-13
		Fannie Mae				Freddie Mac				Ginnie Mae				Total
	Fixed-rate agency RMBS:
	Par value	$	4,461,621			$	1,079,180			$	32,792			$	5,573,593
	Unamortized premium	195,633				50,265				703				246,601
	Amortized cost	4,657,254				1,129,445				33,495				5,820,194
	Gross unrealized gains	4,230				1,570				568				6,368
	Gross unrealized losses	(150,447		)		(34,433		)		—				(184,880		)
	Fixed-rate agency RMBS, at fair value	$	4,511,037			$	1,096,582			$	34,063			$	5,641,682
	Weighted average coupon as of December 31, 2013	3.33		%		3.44		%		3		%		3.35		%
	Weighted average yield as of December 31, 2013	2.53		%		2.67		%		2.12		%		2.56		%
	Weighted average yield for the year ended December 31, 2013	2.69		%		2.87		%		2.22		%		2.72		%
			31-Dec-13
			Amortized Cost				Gross Unrealized Gain				Gross Unrealized Loss				Fair Value
	Agency RMBS:
	Fixed rate		$	5,358,579			$	3,678			$	(184,565	)		$	5,177,692
	Adjustable rate		461,615				2,690				(315		)		463,990
	Total		$	5,820,194			$	6,368			$	(184,880	)		$	5,641,682
	Actual maturities of agency RMBS are generally shorter than the stated contractual maturities. Actual maturities are affected by the contractual lives of the underlying mortgages, periodic principal payments and principal prepayments.
	The following table summarizes our agency RMBS as of September 30, 2014 and December 31, 2013 according to their estimated weighted average life classification (dollars in thousands):
		September 30, 2014														December 31, 2013
										Weighted Average												Weighted Average
	Weighted Average Life	Fair				Amortized				Yield			Coupon			Fair			Amortized			Yield		Coupon
		Value				Cost										Value			Cost
	Less than or equal to three years	$	—			$	—			—	%		—	%		$	9,089		$	9,095		2.38	%	3.49	%
	Greater than three years and less than or equal to five years	1,457,026				1,462,276				2.14	%		3.08	%		2,142,111			2,159,311			2.29	%	3.2	%
	Greater than five years and less than or equal to 10 years	2,763,147				2,808,772				2.81	%		3.55	%		3,485,241			3,646,188			2.72	%	3.43	%
	Greater than 10 years	39,590				39,780				3.19	%		3.64	%		5,241			5,600			2.96	%	3.5	%
	Total	$	4,259,763			$	4,310,828			2.59	%		3.39	%		$	5,641,682		$	5,820,194		2.56	%	3.35	%
	As of September 30, 2014 and December 31, 2013, none of our agency RMBS had an estimated weighted average life of less than 3.4 years and 2.1 years, respectively. As of September 30, 2014 and December 31, 2013, the estimated weighted average life of our agency security portfolio was 7.1 years and 6.1 years, respectively, which incorporates anticipated future prepayment assumptions. As of September 30, 2014 and December 31, 2013, our weighted average expected constant prepayment rate ("CPR") over the remaining life of our aggregate agency investment portfolio was 8% and 7%, respectively. Our estimates differ materially for different types of securities and thus individual holdings have a wide range of projected CPRs. We estimate long-term prepayment rates using a third-party service and market data. We review the prepayment speeds estimated by the third-party service and compare the results to market consensus prepayment speeds, if available. We also consider historical prepayment speeds and current market conditions to validate reasonableness. As market conditions may change rapidly, we use our judgment in developing our estimates for different securities. Prepayments are dependent on many factors and actual prepayments could differ materially from our estimates. Various market participants could use materially different assumptions. Furthermore, changes in market conditions such as interest rates, housing prices, and broad economic factors such as employment can materially impact prepayments. Additionally, modifications to GSE underwriting criteria or programs, GSE policies surrounding the buyouts or modifications of delinquent loans or other factors could significantly change the prepayment landscape.
	Realized Gains and Losses
	The following table summarizes our net realized gains and losses from the sale of agency RMBS during the three and nine months ended September 30, 2014 and 2013 (dollars in thousands):
			For the Three Months Ended September 30,								For the Nine Months Ended September 30,
			2014				2013				2014				2013
	Proceeds from agency RMBS sold		$	400,042			$	2,076,462			$	2,067,118			$	5,356,680
	Increase (decrease) in receivable for agency RMBS sold		(77,918		)		39,397				(570,029		)		201,968
	Less agency RMBS sold, at cost		(321,439		)		(2,187,038		)		(1,505,485		)		(5,642,132		)
	Net realized gain (loss) on sale of agency RMBS		$	685			$	(71,179	)		$	(8,396	)		$	(83,484	)
	Gross realized gains on sale of agency RMBS		$	1,552			$	241			$	9,382			$	18,965
	Gross realized losses on sale of agency RMBS		(867		)		(71,420		)		(17,778		)		(102,449		)
	Net realized gain (loss) on sale of agency RMBS		$	685			$	(71,179	)		$	(8,396	)		$	(83,484	)
	Pledged Assets
The following tables summarize our agency RMBS pledged as collateral under repurchase agreements and derivative agreements by type as of September 30, 2014 and December 31, 2013 (dollars in thousands):
		September 30, 2014
Agency RMBS Pledged		Fannie Mae				Freddie Mac				Total
Under Repurchase Agreements (1)
Fair value		$	2,448,137			$	1,608,806			$	4,056,943
Accrued interest on pledged agency RMBS		6,688				4,378				11,066
Under Derivative Agreements
Fair value		631				—				631
Accrued interest on pledged agency RMBS		2				—				2
Total Fair Value of Agency RMBS Pledged and Accrued Interest		$	2,455,458			$	1,613,184			$	4,068,642
		31-Dec-13
Agency RMBS Pledged		Fannie Mae				Freddie Mac				Ginnie Mae				Total
Under Repurchase Agreements
Fair value		$	4,492,566			$	1,092,106			$	34,063			$	5,618,735
Accrued interest on pledged agency RMBS		12,287				3,078				82				15,447
Total Fair Value of Agency RMBS Pledged and Accrued Interest		$	4,504,853			$	1,095,184			$	34,145			$	5,634,182
————————
-1	Agency RMBS pledged do not include $14.9 million pledged under repurchase agreements related to securities sold but not yet settled as of September 30, 2014.
The following table summarizes our agency RMBS pledged as collateral under repurchase agreements by remaining maturity as of September 30, 2014 and December 31, 2013 (dollars in thousands):
		September 30, 2014												December 31, 2013
Remaining Maturity		Fair Value				Amortized				Accrued Interest				Fair Value			Amortized			Accrued Interest
						Cost											Cost
30 days or less		$	1,643,365			$	1,659,527			$	4,609			$	2,591,560		$	2,672,502		$	7,182
31 - 59 days		731,888				736,700				1,880				1,105,167			1,151,447			3,096
60 - 90 days		545,575				554,329				1,463				1,261,354			1,299,749			3,455
Greater than 90 days		1,136,115				1,155,824				3,114				660,654			673,560			1,714
Total		$	4,056,943			$	4,106,380			$	11,066			$	5,618,735		$	5,797,258		$	15,447
As of September 30, 2014 and December 31, 2013, none of our repurchase agreement borrowings backed by agency RMBS were due on demand or mature overnight.

NonAgency_Securities

Non-Agency Securities	9 Months Ended
	Sep. 30, 2014
Non-agency Securities [Abstract]	'
Non-Agency Securities	'
	Non-Agency Securities
	The following tables summarize our non-agency RMBS as of September 30, 2014 and December 31, 2013 (dollars in thousands):
	September 30, 2014
			Fair			Gross Unrealized							Amortized Cost				Discount				Par/ Current Face				Weighted Average
	Category		Value			Gains			Losses																Coupon (1)			Yield
	Prime (2)		$	257,128		$	16,569		$	(3,126	)		$	243,685			$	(213,015	)		$	456,700			2.29	%		6.56	%
	Alt-A		494,564			42,923			(3,512		)		455,153				(178,394		)		633,547				1.65	%		6.99	%
	Option-ARM		168,928			13,123			(1,430		)		157,235				(43,095		)		200,330				0.49	%		6.25	%
	Subprime		155,247			8,817			(533		)		146,963				(39,711		)		186,674				1.64	%		5.51	%
	Total		$	1,075,867		$	81,432		$	(8,601	)		$	1,003,036			$	(474,215	)		$	1,477,251			1.69	%		6.55	%
	————————
	-1	Coupon rates are floating, except for $2.7 million, $30.2 million and $50.0 million fair value of fixed-rate prime, Alt-A and subprime non-agency RMBS, respectively, as of September 30, 2014.
	(2)	Prime non-agency RMBS include GSE credit risk transfer securities with $69.2 million in fair value and interest only investments with a fair value of $12.4 million and a current face value of $198.3 million as of September 30, 2014.
	31-Dec-13
			Fair			Gross Unrealized							Amortized Cost				Discount				Par/ Current Face				Weighted Average
	Category		Value			Gains			Losses																Coupon (1)			Yield
	Prime (2)		$	195,524		$	14,161		$	(5,658	)		$	187,021			$	(222,436	)		$	409,457			2	%		6.13	%
	Alt-A		467,531			46,311			(3,420		)		424,640				(199,407		)		624,047				1.56	%		7.6	%
	Option-ARM		119,054			14,809			(1,650		)		105,895				(45,367		)		151,262				0.54	%		7.4	%
	Subprime		229,108			21,471			(1,938		)		209,575				(132,577		)		342,152				1.01	%		6.69	%
	Total		$	1,011,217		$	96,752		$	(12,666	)		$	927,131			$	(599,787	)		$	1,526,918			1.46	%		7.07	%
	————————
	-1	Coupon rates are floating, except for $67.4 million, $16.6 million and $51.9 million fair value of fixed-rate prime, Alt-A and subprime non-agency RMBS, respectively, as of December 31, 2013.
	(2)	Prime non-agency RMBS include GSE credit risk transfer securities with $5.3 million in fair value and interest only investments with a fair value of $11.0 million and a current face value of $206.4 million as of December 31, 2013.
	The following table summarizes our non-agency RMBS at fair value, by their estimated weighted average life classifications as of September 30, 2014 and December 31, 2013 (dollars in thousands):
			September 30, 2014												31-Dec-13
	Weighted Average Life		Fair Value			Amortized			Weighted			Weighted Average Coupon			Fair Value				Amortized				Weighted			Weighted Average Coupon
						Cost			Average										Cost				Average
									Yield														Yield
	≤ 5 years		$	360,644		$	342,486		6.06	%		2.53	%		$	203,935			$	194,800			5.59	%		2.19	%
	> 5 to ≤ 7 years		434,783			395,342			7.1	%		1.31	%		211,013				195,913				6.84	%		2.38	%
	>7 years		280,440			265,208			6.36	%		1.45	%		596,269				536,418				7.7	%		1.08	%
	Total		$	1,075,867		$	1,003,036		6.55	%		1.69	%		$	1,011,217			$	927,131			7.07	%		1.46	%
	Our Prime non-agency RMBS include investments in securitization trusts collateralized by prime mortgage loans, which are residential mortgage loans that are considered to have been originated with the most stringent underwriting standards at the time of origination. Our Prime securities with a combined fair value of $175.6 million as of September 30, 2014 are collateralized by loans that were originated between 2003 and 2006, a period of generally weaker underwriting standards and elevated housing prices. As a result, there is still material credit risk embedded in these vintages. As of September 30, 2014, Prime securities also include $81.5 million in fair value of securities with underlying mortgage loans that were originated with more stringent underwriting during 2012 and 2013. As of September 30, 2014, our Prime securities have both floating-rate and fixed-rate coupons ranging from 0.8% to 6.5%, with weighted average coupons of underlying collateral ranging from 2.4% to 5.8%.
	Our Alt-A non-agency RMBS are collateralized by Alt-A mortgage loans that were originated from 2002 to 2007. Alt-A, or alternative A-paper, mortgage loans are considered to have more credit risk than prime mortgage loans and less credit risk than sub-prime mortgage loans. Alt-A loans are typically characterized by borrowers with less than full documentation, lower credit scores, higher loan-to-value ratios and a higher percentage of investment properties. As of September 30, 2014, our Alt-A securities have both fixed and floating rate coupons ranging from 0.2% to 6.5% with weighted average coupons of underlying collateral ranging from 2.7% to 6.9%.
	Our Option-ARM non-agency RMBS include senior tranches in securitization trusts that are collateralized by residential mortgages that have origination and underwriting characteristics similar to Alt-A mortgage loans, with the added feature of providing underlying mortgage borrowers the option, within certain constraints, to make lower payments than otherwise required by the stated interest rate for a number of years, leading to negative amortization and increased loan balances. This additional feature can increase the credit risk of these securities. As of September 30, 2014, our Option-ARM securities have coupons ranging from 0.3% to 1.1% and have underlying collateral with weighted average coupons between 2.7% and 3.5%. The loans underlying our Option-ARM securities were originated between 2004 and 2007.
	Our Subprime non-agency RMBS issued prior to 2013 include fixed and floating rate, senior tranches in securitization trusts collateralized by residential mortgages originated from 2003 to 2007 that were originally considered to be of lower credit quality. As of September 30, 2014, our Subprime securities issued prior to 2013 have a fair value of $139.6 million with fixed and floating rate coupons ranging from 0.2% to 5.4% and have underlying collateral with weighted-average coupons ranging from 4.5% to 7.8%. Additionally, we have classified certain non-performing loans that were securitized in 2013 and 2014 as Subprime securities. These 2013 and 2014 securitizations are backed by loans originated during or before 2010 and, as of September 30, 2014, have a fair value of $15.6 million. As of September 30, 2014, our Subprime securities issued in 2013 and 2014 have fixed rate coupons ranging from 3.3% to 4.3% and have underlying collateral with weighted-average coupons ranging from 5.7% to 8.4%.
	More than 98% of our non-agency RMBS are rated below investment grade or have not been rated by credit agencies as of September 30, 2014.
	Realized Gains and Losses
	The following table summarizes our net realized gains and losses from the sale of non-agency RMBS during the three and nine months ended September 30, 2014 and 2013 (dollars in thousands):
			For the Three Months Ended September 30,						For the Nine Months Ended September 30,
			2014			2013			2014				2013
	Proceeds from non-agency RMBS sold		$	166,204		$	41,026		$	461,415			$	160,405
	Increase (decrease) in receivable for non-agency RMBS sold		10,514			—			10,514				—
	Less: non-agency RMBS sold, at cost		(159,315		)	(35,142		)	(440,134		)		(144,795		)
	Net realized gain on sale of non-agency RMBS		$	17,403		$	5,884		$	31,795			$	15,610
	Gross realized gain on sale of non-agency RMBS		$	18,436		$	6,836		$	36,731			$	17,543
	Gross realized loss on sale of non-agency RMBS		(1,033		)	(952		)	(4,936		)		(1,933		)
	Net realized gain on sale of non-agency RMBS		$	17,403		$	5,884		$	31,795			$	15,610
	Pledged Assets
	Non-agency RMBS with a fair value of $0.8 billion and $0.9 billion were pledged as collateral under repurchase agreements as of September 30, 2014 and December 31, 2013, respectively. As of September 30, 2014 and December 31, 2013, none of our repurchase agreement borrowings backed by non-agency RMBS were due on demand or mature overnight.
	The following table summarizes our non-agency RMBS pledged as collateral under repurchase agreements by remaining maturity as of September 30, 2014 and December 31, 2013 (dollars in thousands):
			September 30, 2014										December 31, 2013
	Remaining Maturity		Fair Value			Amortized			Accrued Interest				Fair Value				Amortized				Accrued Interest
						Cost											Cost
	30 days or less		$	701,439		$	649,382		$	998			$	547,087			$	502,063			$	857
	31 - 59 days		90,035			79,064			66				70,478				68,622				57
	60 - 90 days		38,367			34,275			41				64,873				58,091				55
	Greater than 90 days		16,020			16,799			11				216,738				196,644				242
	Total		$	845,861		$	779,520		$	1,116			$	899,176			$	825,420			$	1,211
	————————
	-1	Non-agency RMBS pledged do not include $10.5 million pledged under repurchase agreements related to securities sold but not yet settled as of September 30, 2014.

Repurchase_Agreements

Repurchase Agreements	9 Months Ended
	Sep. 30, 2014
Disclosure of Repurchase Agreements [Abstract]	'
Repurchase Agreements	'
	Repurchase Agreements
	We pledge certain of our securities as collateral under repurchase arrangements with financial institutions, the terms and conditions of which are negotiated on a transaction-by-transaction basis. Interest rates on these borrowings are generally based on LIBOR plus or minus a margin and amounts available to be borrowed are dependent upon the fair value of the securities pledged as collateral, which fluctuates with changes in interest rates, type of security and liquidity conditions within the banking, mortgage finance and real estate industries. In response to declines in fair value of pledged securities, lenders may require us to post additional collateral or pay down borrowings to re-establish agreed upon collateral requirements, referred to as margin calls. As of September 30, 2014 and December 31, 2013, we have met all margin call requirements and had no agency or non-agency repurchase agreements with original overnight maturities. Repurchase agreements are carried at cost, which approximates fair value due to their short-term nature.
	At September 30, 2014 and December 31, 2013, our borrowings under repurchase agreements had the following collateral characteristics (dollars in thousands):
		September 30, 2014					December 31, 2013
				Weighted Average					Weighted Average
	Collateral Type	Borrowings		Interest Rate		Days	Borrowings		Interest Rate		Days
		Outstanding				to Maturity	Outstanding				to Maturity
	Agency securities	$	3,814,485	0.39	%	99	$	5,935,610	0.43	%	96
	Non-agency securities	646,793		1.7	%	22	647,068		1.79	%	33
	Treasury securities	460,534		0.02	%	7	575,514		0.07	%	2
	Total repurchase agreements	$	4,921,812	0.52	%	80	$	7,158,192	0.52	%	83
	The following table summarizes our borrowings under repurchase arrangements and weighted average interest rates classified by remaining maturities as of September 30, 2014 and December 31, 2013 (dollars in thousands):
		September 30, 2014					December 31, 2013
				Weighted Average					Weighted Average
		Borrowings		Interest Rate		Days	Borrowings		Interest Rate		Days
		Outstanding				to Maturity	Outstanding				to Maturity
	Agency and non-agency repurchase agreements
	≤ 1 month	$	2,113,444	0.67	%	12	$	3,047,986	0.6	%	14
	> 1 to ≤ 2 months	797,223		0.51	%	50	816,960		0.55	%	45
	> 2 to ≤ 3 months	569,354		0.44	%	77	1,506,888		0.52	%	77
	> 3 to ≤ 6 months	401,830		0.48	%	137	621,124		0.54	%	135
	> 6 to ≤ 9 months	305,480		0.47	%	242	147,729		0.49	%	249
	> 9 to ≤ 12 months	23,947		0.48	%	290	191,991		0.5	%	321
	> 12 months	250,000		0.59	%	580	250,000		0.59	%	853
	Total	4,461,278		0.58	%	87	6,582,678		0.56	%	90
	U.S. Treasury repurchase agreements
	Short-term	460,534		0.02	%	7	575,514		0.07	%	2
	Total repurchase agreements	$	4,921,812	0.52	%	80	$	7,158,192	0.52	%	83
	We had repurchase agreements with 33 and 31 financial institutions as of September 30, 2014 and December 31, 2013, respectively. In addition, less than 5% of stockholders' equity was at risk due to collateral pledged in excess of borrowings under repurchase agreements with any one counterparty, with the top five counterparties representing less than 18% of our equity at risk as of September 30, 2014.
	We had agency RMBS with fair values of $4.1 billion and $5.6 billion and non-agency RMBS with fair values of $0.8 billion and $0.9 billion pledged as collateral against repurchase agreements, as of September 30, 2014 and December 31, 2013, respectively.

Derivatives

Derivatives	9 Months Ended
	Sep. 30, 2014
Derivative Instruments [Abstract]	'
Derivative Instruments and Hedging Activities Disclosure [Text Block]	'
	Derivatives and Other Securities
	In connection with our risk management strategy, we hedge a portion of our exposure to market risks, including interest rate risk and prepayment risk, by entering into derivative and other hedging instrument contracts. We may enter into agreements for interest rate swaps, interest rate swaptions, interest rate cap or floor contracts and futures or forward contracts. We may also purchase or short TBA and U.S. Treasury securities, purchase or write put or call options on TBA securities or we may invest in other types of derivative securities, including synthetic total return swaps and credit default swaps. Our risk management strategy attempts to manage the overall risk of the portfolio and reduce fluctuations in book value. We do not use derivative or other hedging instruments for speculative purposes. Derivatives have not been designated as hedging instruments. We do not offset our derivatives and related cash collateral with the same counterparties under any master netting arrangements. For additional information regarding our derivative instruments and our overall risk management strategy, please refer to the discussion of derivatives in Note 3 - Summary of Significant Accounting Policies.
	The table below presents the balance sheet location and fair value information for our derivatives outstanding as of September 30, 2014 and December 31, 2013 (in thousands):
			30-Sep-14				31-Dec-13
	Interest rate swaps		$	20,480			$	51,957
	Interest rate swaptions		7,603				50,009
	U.S. Treasury futures		1,196				3,399
	TBA securities		3,662				2,856
	Mortgage options		7				—
	Derivative assets, at fair value		$	32,948			$	108,221
	Interest rate swaps		$	42,950			$	9,490
	TBA securities		5,730				1,837
	Mortgage options		62				—
	Derivative liabilities, at fair value		$	48,742			$	11,327
	The following tables summarize the effect of our outstanding derivatives and other securities on our consolidated statements of operations during the three and nine months ended September 30, 2014 and 2013 (in thousands):
			For the Three Months Ended September 30,
			2014										2013
			Realized Loss on Periodic Settlements of Interest Rate Swaps, net			Realized Gain on Other Derivatives and Securities, net			Unrealized Gain (Loss) on Other Derivatives and Securities, net				Realized Loss on Periodic Settlements of Interest Rate Swaps, net			Realized Gain on Other Derivatives and Securities, net			Unrealized Gain (Loss) on Other Derivatives and Securities, net
	Interest rate swaps		$	(5,226	)	$	—		$	13,445			$	(14,449	)	$	53,365		$	(53,588	)
	Interest rate swaptions		—			(719		)	(514		)		—			18,625			(32,498		)
	TBA securities		—			16,840			(15,004		)		—			(42,505		)	3,433
	U.S. Treasuries		—			(222		)	(145		)		—			(12,716		)	18,140
	U.S. Treasury futures		—			(653		)	559				—			6,650			(9,930		)
	Short sales of U.S. Treasuries		—			(2,964		)	(377		)		—			41,839			(30,695		)
	REIT equity investments		—			1,188			(1,375		)		—			—			—
	Mortgage options		—			234			108				—			—			—
	Total		$	(5,226	)	$	13,704		$	(3,303	)		$	(14,449	)	$	65,258		$	(105,138	)
			For the Nine Months Ended September 30,
			2014										2013
			Realized Loss on Periodic Settlements of Interest Rate Swaps, net			Realized Gain on Other Derivatives and Securities, net			Unrealized Gain (Loss) on Other Derivatives and Securities, net				Realized Loss on Periodic Settlements of Interest Rate Swaps, net			Realized Gain on Other Derivatives and Securities, net			Unrealized Gain (Loss) on Other Derivatives and Securities, net
	Interest rate swaps		$	(15,400	)	$	68		$	(64,757	)		$	(32,228	)	$	53,365		$	123,930
	Interest rate swaptions		—			(17,551		)	(8,882		)		—			15,193			11,398
	TBA securities		—			22,832			(3,086		)		—			(23,119		)	(50,095		)
	U.S. Treasuries		—			2,536			12,293				—			(13,786		)	7,489
	U.S. Treasury futures		—			(4,630		)	(2,202		)		—			9,353			(2,743		)
	Short sales of U.S. Treasuries		—			(8,928		)	(5,444		)		—			45,669			2,939
	REIT equity investments					8,675			502				—			—			—
	Mortgage options		—			234			(32		)					—			—
	Total		$	(15,400	)	$	3,236		$	(71,608	)		$	(32,228	)	$	86,675		$	92,918
	The following tables summarize changes in notional amounts for our outstanding derivatives and other securities for the nine months ended September 30, 2014 and 2013 (in thousands):
		31-Dec-13				Additions/ Long Positions			Expirations/			30-Sep-14
		Notional							Terminations/ Short Positions			Notional
		Amount										Amount
	Interest rate swaps	$	3,240,000			875,000			(150,000	)		$	3,965,000
	Interest rate swaptions	$	2,100,000			275,000			(1,900,000	)		$	475,000
	TBA securities	$	(773,816	)		15,525,174			(13,834,986	)		$	916,372
	U.S. Treasuries	$	656,000			832,570			(1,016,570	)		$	472,000
	U.S. Treasury futures	$	(150,000	)		450,000			(450,000	)		$	(150,000	)
	Short sales of U.S. Treasuries	$	(23,000	)		1,085,500			(1,797,000	)		$	(734,500	)
	Mortgage options	$	—			100,000			(200,000	)		$	(100,000	)
		31-Dec-12				Additions/ Long Positions			Expirations/			30-Sep-13
		Notional							Terminations/ Short Positions			Notional
		Amount										Amount
	Interest rate swaps	$	2,940,000			2,900,000			(1,450,000	)		$	4,390,000
	Interest rate swaptions	$	1,150,000			2,150,000			(1,100,000	)		$	2,200,000
	TBA securities	$	(522,188	)		7,109,859			(8,195,521	)		$	(1,607,850	)
	U.S. Treasuries	$	—			3,865,000			(3,005,000	)		$	860,000
	U.S. Treasury futures	$	—			500,000			(650,000	)		$	(150,000	)
	Short sales of U.S. Treasuries	$	(425,000	)		3,200,000			(2,775,000	)		$	—
	Interest Rate Swap Agreements
	As of September 30, 2014 and December 31, 2013, our derivative portfolio included interest rate swaps, which have the effect of modifying the repricing characteristics of our repurchase agreements and cash flows on such liabilities. Our interest rate swaps are used to manage the interest rate risk created by our use of short-term repurchase agreements. Under our interest rate swaps, we typically pay a fixed rate and receive a floating rate based on LIBOR with terms usually ranging up to 15 years. As of September 30, 2014 and December 31, 2013, we had interest rate swap agreements summarized in the tables below (dollars in thousands).
					30-Sep-14								31-Dec-13
	Interest Rate Swaps		Balance Sheet Location		Notional Amount				Fair Value				Notional Amount				Fair Value
Interest rate swap assets		Derivative assets, at fair value		$	1,350,000			$	20,480			$	2,275,000			$	51,957
Interest rate swap liabilities		Derivative liabilities, at fair value		2,615,000				(42,950		)		965,000				(9,490		)
				$	3,965,000			$	(22,470	)		$	3,240,000			$	42,467
September 30, 2014
		Notional				Fair Value				Weighted Average
		Amount
Current Maturity Date for Interest Rate Swaps (1)										Fixed			Receive			Maturity
										Pay Rate (2)			Rate (3)			(Years)
≤ 3 years		$	840,000			$	(5,339	)		1.04	%		0.23	%		1.5
> 3 to ≤ 5 years		1,075,000				7,454				1.58	%		0.23	%		4
> 5 to ≤ 7 years		1,050,000				(3,235		)		2.44	%		0.23	%		5.8
> 7 years		1,000,000				(21,350		)		3.16	%		0.23	%		8.2
Total		$	3,965,000			$	(22,470	)		2.09	%		0.23	%		5
December 31, 2013
		Notional				Fair Value				Weighted Average
Current Maturity Date for Interest Rate Swaps (4)		Amount								Fixed			Receive			Maturity
										Pay Rate (2)			Rate (3)			(Years)
≤ 3 years		$	650,000			$	(6,612	)		0.87	%		0.24	%		1.4
> 3 to ≤ 5 years		815,000				4,722				1.11	%		0.24	%		3.9
> 5 to ≤ 7 years		1,025,000				21,434				2.28	%		0.24	%		6.4
> 7 years		750,000				22,923				3.12	%		0.24	%		9.1
Total		$	3,240,000			$	42,467			1.9	%		0.24	%		5.4
————————
(1)	Includes swaps with an aggregate notional of $1.9 billion with deferred start dates averaging 1.2 years from September 30, 2014.
(2)	Excluding forward starting swaps, the weighted average pay rate was 1.25% and 1.18% as of September 30, 2014 and December 31, 2013, respectively.
(3)	Weighted average receive rate excludes impact of forward starting interest rate swaps.
(4)	Includes swaps with an aggregate notional of $1.2 billion with deferred start dates averaging 1.9 years from December 31, 2013.
As of September 30, 2014, interest rate swaps with an asset fair value of $0.8 million and notional amount of $375.0 million and a liability fair value of $(37.3) million and notional amount of $1.7 billion were centrally cleared on a registered exchange.
Interest Rate Swaption Agreements
Our interest rate swaption agreements provide us the option to enter into interest rate swap agreements in the future where we would pay a fixed rate and receive LIBOR. The following tables present certain information about our interest rate swaption agreements as of September 30, 2014 and December 31, 2013 (dollars in thousands):
September 30, 2014
		Option										Underlying Swap
Current Option Expiration Date		Cost				Fair Value				Weighted Average Years to Expiration		Notional Amount				Pay Rate			Weighted Average Term (Years)
≤ 3 months		$	179			$	88			0		$	50,000			1.3	%		3
> 3 to ≤ 12 months		4,765				2,835				0.7		100,000				3.34	%		7
>12 to ≤ 24 months		1,308				635				1.5		100,000				4.13	%		7
> 24 months		3,946				4,045				2.7		225,000				2.97	%		3.7
Total / weighted average		$	10,198			$	7,603			1.8		$	475,000			3.11	%		5
December 31, 2013
		Option										Underlying Swap
Current Option Expiration Date		Cost				Fair Value				Weighted Average Years to Expiration		Notional Amount				Pay Rate			Weighted Average Term (Years)
≤ 3 months		$	17,015			$	19,841			0.1		$	925,000			2.59	%		8
> 3 to ≤ 12 months		13,868				10,406				0.6		550,000				2.94	%		8.2
>12 to ≤ 24 months		8,105				8,979				1.7		400,000				3.63	%		6.3
> 24 months		4,734				10,783				3.2		225,000				3.62	%		5.9
Total / weighted average		$	43,722			$	50,009			0.9		$	2,100,000			2.99	%		7.5
TBA Securities
As of September 30, 2014 and December 31, 2013, we had contracts to purchase ("long position") and sell ("short position") TBA securities on a forward basis, presented in the following table (in thousands):
		30-Sep-14								31-Dec-13
Purchase and Sale Contracts for TBA Securities		Notional				Fair				Notional				Fair
		Amount (1)				Value (2)				Amount (1)				Value (2)
TBA assets
Purchase of TBA securities		$	1,005,970			$	3,449			$	210,600			$	158
Sale of TBA securities		(100,578		)		213				(463,496		)		2,698
Total TBA assets		905,392				3,662				(252,896		)		2,856
TBA liabilities
Purchase of TBA securities		433,080				(3,808		)		—				—
Sale of TBA securities		(422,100		)		(1,922		)		(520,920		)		(1,837		)
Total TBA liabilities		10,980				(5,730		)		(520,920		)		(1,837		)
Total net TBA		$	916,372			$	(2,068	)		$	(773,816	)		$	1,019
————————
(1)	Notional amount represents the par value or principal balance of the underlying agency security.
(2)	Fair value represents the current market value of the agency RMBS underlying the TBA contract as of period end, less the forward price to be paid for the underlying agency RMBS.
U.S. Treasury Securities and Futures
We purchase or sell short U.S. Treasury securities and U.S. Treasury futures contracts to help mitigate the potential impact of changes in interest rates on the performance of our portfolio. We had U.S. Treasury securities with a fair value of $467.2 million and $637.3 million and a face amount of $472.0 million and $656.0 million as of September 30, 2014 and December 31, 2013, respectively, which is presented as Treasury securities, at fair value on the consolidated balance sheets. In addition, we had a short position in U.S. Treasury futures with a fair value of $1.2 million and $3.4 million, respectively, and a notional amount of $(150.0) million as of both September 30, 2014 and December 31, 2013, which is presented in derivative assets, at fair value on the consolidated balance sheets.
We had obligations to return U.S. Treasury securities borrowed under reverse repurchase agreements accounted for as securities borrowing transactions with a fair value of $742.6 million and $22.5 million as of September 30, 2014 and December 31, 2013, respectively. The borrowed securities were collateralized by cash payments of $745.4 million and $22.7 million as of September 30, 2014 and December 31, 2013, respectively, which are presented as receivables under reverse repurchase agreements on the consolidated balance sheets. All changes in fair value of long and short U.S. Treasury securities and futures are recorded in unrealized gain (loss) on other derivatives and securities, net in our consolidated statements of operations.
REIT Equity Securities, at Fair Value
As of December 31, 2013, we held shares of common stock of several publicly-traded mortgage REITs with a cost basis of $39.3 million and a total fair value of $38.8 million. As of September 30, 2014, we no longer held any positions in these securities and for the nine months ended September 30, 2014, we recognized $6.8 million of net realized gains on disposal and $1.8 million in dividend income which are both included in realized gain on other derivatives and securities, net in our consolidated statements of operations.
Credit Risk-Related Contingent Features
The use of derivatives creates exposure to credit risk relating to potential losses that could be recognized in the event that the counterparties to these instruments fail to perform their obligations under the contracts. We minimize this risk by limiting our counterparties for instruments which are not centrally cleared on a registered exchange to major financial institutions with acceptable credit ratings and monitoring positions with individual counterparties. In addition, both we and our counterparties may be required to pledge assets as collateral for our derivatives, whose amounts vary over time based on the market value, notional amount and remaining term of the derivative contract. In the event of a default by a counterparty, we may not receive payments provided for under the terms of our derivative agreements, and may have difficulty obtaining our assets pledged as collateral for our derivatives. The cash and cash equivalents pledged as collateral for our derivative instruments is included in restricted cash and cash equivalents on our consolidated balance sheets.
Each of our ISDA Master Agreements contains provisions pursuant to which we are required to fully collateralize our obligations under our interest rate swap agreements if at any point the fair value of the swap represents a liability greater than the minimum transfer amount contained within our ISDA Master Agreements. We are also required to post initial collateral upon execution of certain of our swap transactions. If we breach any of these provisions, we will be required to settle our obligations under the agreements at their termination values, which approximates fair value.
Further, each of our ISDA Master Agreements also contains a cross default provision under which a default under certain of our other indebtedness in excess of a certain threshold causes an event of default under the agreement. Threshold amounts vary by lender. Following an event of default, we could be required to settle our obligations under the agreements at their termination values. Additionally, under certain of our ISDA Master Agreements, we could be required to settle our obligations under the agreements at their termination values if we fail to maintain either our REIT status or certain minimum stockholders’ equity thresholds, or comply with limits on our leverage above certain specified levels. As of September 30, 2014, the fair value of the additional collateral that could be required to be posted as a result of the credit-risk related contingent features being triggered was not material to our consolidated financial statements.
Concerning our non-centrally cleared interest rate swap and swaption agreements, we did not have counterparty credit risk with any single counterparty in excess of 1% of our stockholders’ equity, as of September 30, 2014.
In the case of centrally cleared interest rate swap contracts, we could be exposed to credit risk if the central clearing agency or a clearing member defaults on its respective obligation to perform under the contract; however, the risk is considered minimal due to initial and daily exchange of mark to market margin requirements and the clearinghouse guarantee fund and other resources that are available in the event of a clearing member default.

Offsetting_Assets_and_Liabilit

Offsetting Assets and Liabilities (Notes)	9 Months Ended
	Sep. 30, 2014
Offsetting Assets and Liabilities [Abstract]	'
Offsetting Assets and Liabilities [Text Block]	'
	Offsetting Assets and Liabilities
	Certain of our repurchase agreements and derivative transactions are governed by underlying agreements that generally provide for a right of offset under master netting arrangements (or similar agreements), including in the event of default or in the event of bankruptcy of either party to the transactions.  We present our assets and liabilities subject to such arrangements on a gross basis in our consolidated balance sheets.
	The following tables present information about our assets and liabilities that are subject to such agreements and can potentially be offset on our consolidated balance sheets as of September 30, 2014 and December 31, 2013 (in thousands):
	Offsetting of Financial Assets and Derivative Assets:
			Gross Amounts of Recognized Assets		Gross Amounts Offset in the Consolidated Balance Sheets		Net Amounts Presented		Gross Amounts Not Offset in the Consolidated Balance Sheets
							in the Consolidated Balance Sheets		Financial Instruments			Collateral Received (2)			Net Amount
	September 30, 2014
	Interest rate swaps and swaptions (1)		$	28,083	$	—	$	28,083	$	(6,288	)	$	(8,205	)	$	13,590
	Receivable under reverse repurchase agreements		745,443		—		745,443		(566,887		)	(176,990		)	1,566
	Total		$	773,526	$	—	$	773,526	$	(573,175	)	$	(185,195	)	$	15,156
	December 31, 2013
	Interest rate swaps and swaptions (1)		$	101,966	$	—	$	101,966	$	(9,490	)	$	(45,084	)	$	47,392
	Receivable under reverse repurchase agreements		22,736		—		22,736		(22,736		)	—			—
	Total		$	124,702	$	—	$	124,702	$	(32,226	)	$	(45,084	)	$	47,392
	Offsetting of Financial Liabilities and Derivative Liabilities:
			Gross Amounts of Recognized Liabilities		Gross Amounts Offset in the Consolidated Balance Sheets		Net Amounts Presented		Gross Amounts Not Offset in the Consolidated Balance Sheets
							in the Consolidated Balance Sheets		Financial Instruments			Collateral Pledged (2)			Net Amount
	September 30, 2014
	Interest rate swaps (1)		$	42,950	$	—	$	42,950	$	(6,288	)	$	(36,662	)	$	—
	Repurchase agreements		4,921,812		—		4,921,812		(566,887		)	(4,354,925		)	—
	Total		$	4,964,762	$	—	$	4,964,762	$	(573,175	)	$	(4,391,587	)	$	—
	December 31, 2013
	Interest rate swaps (1)		$	9,490	$	—	$	9,490	$	(9,490	)	$	—		$	—
	Repurchase agreements		7,158,192		—		7,158,192		(22,736		)	(7,135,456		)	—
	Total		$	7,167,682	$	—	$	7,167,682	$	(32,226	)	$	(7,135,456	)	$	—
	————————
	-1	Reported under derivative assets / liabilities, at fair value in the accompanying consolidated balance sheets. Refer to Note 7 for a reconciliation of derivative assets / liabilities, at fair value to their sub-components.
	-2	Includes cash and securities received / pledged as collateral, at fair value. Amounts presented are limited to collateral pledged sufficient to reduce the net amount to zero on a counterparty by counterparty basis, as applicable. Refer to Notes 4 and 5 for additional information regarding assets pledged as collateral.

Fair_Value_Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2014
Fair Value Disclosures [Abstract]	'
Fair Value Disclosures [Text Block]	'
	Fair Value Measurements
	We have elected the option to account for all of our financial assets, including RMBS, at fair value, with changes in fair value reflected in income during the period in which they occur. We have determined that this presentation most appropriately represents our financial results and position. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date, based on the assumptions market participants would use when pricing an asset or liability.
	We determine the fair value of our agency and non-agency RMBS, including securities held as collateral, based upon fair value estimates obtained from multiple third-party pricing services and dealers. In determining fair value, third-party pricing sources use various valuation approaches, including market and income approaches. Factors used by third-party sources in estimating the fair value of an instrument may include observable inputs such as recent trading activity, credit data, volatility statistics, and other market data that are current as of the measurement date. The availability of observable inputs can vary by instrument and is affected by a wide variety of factors, including the type of instrument, whether the instrument is new and not yet established in the marketplace and other characteristics particular to the instrument. Third-party pricing sources may also use certain unobservable inputs, such as assumptions of future levels of prepayment, default and loss severity, especially when estimating fair values for securities with lower levels of recent trading activity. When possible, we make inquiries of third-party pricing sources to understand their use of significant inputs and assumptions.
	We review the various third-party fair value estimates and perform procedures to validate their reasonableness, including an analysis of the range of third-party estimates for each position, comparison to recent trade activity for similar securities, and our Manager's review for consistency with market conditions observed as of the measurement date. While we do not adjust prices we obtain from third-party pricing sources, we will exclude third-party prices for securities from our determination of fair value if we determine (based on our validation procedures and our Manager's market knowledge and expertise) that the price is significantly different than observable market data would indicate and we cannot obtain a satisfactory understanding from the third party source as to the significant inputs used to determine the price.
	We determine the fair value of our MSR based upon discounted cash flow models that are primarily based on observable market-based inputs but also include substantial unobservable market data inputs (including prepayment speeds, delinquency levels and discount rates).
	We utilize a three-level valuation hierarchy for disclosure of fair value measurement. The valuation hierarchy is based upon the transparency of inputs to the valuation of an asset or liability as of the measurement date. A financial instrument’s categorization within the hierarchy is based upon the lowest level of input that is significant to the fair value measurement. We use the results of the validation procedures described above as part of our determination of the appropriate fair value measurement hierarchy classification. The three levels of hierarchy are defined as follows:
	•	Level 1 Inputs - Quoted prices (unadjusted) for identical unrestricted assets and liabilities in active markets that are accessible at the measurement date.
	•	Level 2 Inputs - Quoted prices for similar assets and liabilities in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations whose inputs are observable or whose significant value drivers are observable.
	•	Level 3 Inputs - Significant unobservable market inputs that are supported by little or no market activity. The unobservable inputs represent the assumptions that market participants would use to price the assets and liabilities.
	The following tables present our financial instruments carried at fair value as of September 30, 2014 and December 31, 2013, on the consolidated balance sheets by the valuation hierarchy, as described above (in thousands):
			September 30, 2014
			Level 1			Level 2			Level 3			Total
	Assets
	Agency RMBS		$	—		$	4,259,763		$	—		$	4,259,763
	Non-agency RMBS		—			1,075,867			—			1,075,867
	U.S. Treasury securities		467,201			—			—			467,201
	Derivative assets		—			32,948			—			32,948
	MSR assets		—			—			100,314			100,314
	Total		$	467,201		$	5,368,578		$	100,314		$	5,936,093
	Liabilities
	Derivative liabilities		$	—		$	48,742		$	—		$	48,742
	Obligation to return securities borrowed under reverse repurchase agreements		742,642			—			—			742,642
	MSR financing liabilities		—			—			14,470			14,470
	Total		$	742,642		$	48,742		$	14,470		$	805,854
			December 31, 2013
			Level 1			Level 2			Level 3			Total
	Assets
	Agency RMBS		$	—		$	5,641,682		$	—		$	5,641,682
	Non-agency RMBS		—			1,011,217			—			1,011,217
	REIT equity securities		38,807			—			—			38,807
	U.S. Treasury securities		637,342			—			—			637,342
	Derivative assets		—			108,221			—			108,221
	MSR assets		—			—			15,608			15,608
	Total		$	676,149		$	6,761,120		$	15,608		$	7,452,877
	Liabilities
	Derivative liabilities		$	—		$	11,327		$	—		$	11,327
	Obligation to return securities borrowed under reverse repurchase agreements		22,530			—			—			22,530
	MSR financing liabilities		—			—			15,608			15,608
	Total		$	22,530		$	11,327		$	15,608		$	49,465
	Our agency and non-agency RMBS are valued using the various market data described above, which include inputs determined to be observable or whose significant value drivers are observable. Accordingly, our agency and non-agency RMBS are classified as Level 2 in the fair value hierarchy as of September 30, 2014. We estimate the fair value of our REIT equity securities on a market approach using Level 1 inputs, based on quoted market prices.
	For information regarding valuation of our derivative instruments, please refer to the discussion of derivative and other hedging instruments in Note 3. Our interest rate swaps and other derivatives are classified as Level 2 in the fair value hierarchy.
	The fair value of our obligation to return securities borrowed under reverse repurchase agreements is based upon the value of the underlying borrowed U.S. Treasury securities as of the reporting date. Both U.S. Treasury securities and our obligation to return borrowed U.S. Treasury securities are classified as Level 1 in the fair value hierarchy.
	The following table presents a summary of the changes in fair value for Level 3 assets carried at fair value as of September 30, 2014 (in thousands):
			For the Nine Months Ended September 30, 2014
			MSR Under Secured Financing (1)			Purchased MSR			Total MSR
	Balance as of December 31, 2013		$	15,608		$	—		$	15,608
	Gains/(losses) included in net income:
	Realized gains (losses)		(968		)	(2,830		)	(3,798		)
	Unrealized gains (losses)		(170		)	(3,705		)	(3,875		)
	Total net gains/(losses) included in net income		(1,138		)	(6,535		)	(7,673		)
	Purchases, net of purchase price adjustments		—			92,379			92,379
	Balance as of September 30, 2014		$	14,470		$	85,844		$	100,314
	————————
	-1	Gains (losses) included in net income related to MSR under secured financing are offset in their entirety by (losses) gains associated with related MSR financing liabilities.
	We use third-party pricing providers in the fair value measurement of our Level 3 MSR. The significant unobservable inputs used in estimating the fair value measurement of our Level 3 MSR assets and financing liabilities include assumptions for underlying loan constant prepayment rates and delinquency rates, as well as discount rates. We review the various third-party fair value estimates used to determine the fair value of our MSR and perform procedures to validate their reasonableness. In reviewing the estimated fair values of our Level 3 MSR, we use internal models and our own estimates of prepayment and
	delinquency rates on the loans underlying our MSR.
	The following table presents the range of our estimates of loan constant voluntary prepayment rates and constant default rates, together with the discount rates used by third-party pricing providers in estimating the fair value of our Level 3 MSR as of September 30, 2014 (dollars in thousands):
			September 30, 2014
	Unobservable Level 3 Input		Fair Value			Minimum		Weighted	Maximum
								Average
	MSR treated as financing arrangements:		$	14,470
	Constant prepayment rate					9.70%		14.70%	34.50%
	Constant default rate					—%		7.40%	28.20%
Discount rate					16.00%		16.00%	16.00%
Purchased MSR:		85,844
Constant prepayment rate					7.30%		7.70%	8.10%
Constant default rate					0.20%		0.30%	0.40%
Discount rate					8.30%		8.70%	9.30%
Total		$	100,314
Our MSR treated as financing arrangements relate to private label mortgages with an average origination year of 2005, whereas our purchased MSR relate to more recently originated mortgages that conform to GSE underwriting standards. Private label originations from the pre-2009 era have experienced heightened default rates relative to recently originated conforming mortgages. As such, we anticipate that the default rate and discount rate for our MSR treated as financing arrangements will exceed the default rate and discount rate for our purchased MSR.
A significant increase in any one of these individual inputs in isolation would likely result in a decrease in fair value measurement. Additionally, a change in the assumption used for discount rates may be accompanied by a directionally similar change in the assumption used for the probability of delinquency and a directionally opposite change in the assumption used for prepayment rates. Overall MSR market conditions could have a more significant impact on our Level 3 fair values than changes in any one unobservable input.

Mortgage_Servicing_Rights_Note

Mortgage Servicing Rights (Notes)	9 Months Ended
	Sep. 30, 2014
Servicing Assets at Fair Value [Line Items]	'
Transfers and Servicing of Financial Assets [Text Block]	'
	Mortgage Servicing Rights
	Our $100.3 million balance of MSR as of September 30, 2014 includes $14.5 million related to RCS' acquisition of certain MSR covering private label residential mortgage pools, for which RCS entered into sale and assignment agreements with a third party to transfer its interest in the excess MSR while retaining the actual servicing function. These transfers do not qualify for sale accounting and are treated as financing arrangements, under which we recognize both MSR assets and MSR corresponding MSR financing liabilities. Changes in the fair value of assets and liabilities resulting from MSR financing transactions have no net impact on the consolidated statements of operations.
	The remaining $85.8 million of MSR were purchased by RCS during the nine months ended September 30, 2014 under transactions qualifying for sale accounting, representing approximately 34,608 underlying loans, with a combined unpaid principal balance of approximately $7.3 billion as of September 30, 2014. We have elected to account for all MSR assets and MSR financing liabilities at estimated fair value with changes in fair value reported in net income. The following table summarizes activity related to MSR accounted for as purchases during the nine months ended September 30, 2014 (dollars in thousands):
			For the Nine Months Ended September 30, 2014
	Balance as of December 31, 2013		$	—
	Additions from purchases of MSR		93,414
	Changes in fair value due to:
	Changes in valuation inputs or assumptions used in valuation model		(3,705		)
	Other changes in fair value (1)		(2,830		)
	Other changes (2)		(1,035		)
	Balance as of September 30, 2014		$	85,844
	————————
	1	Other changes in fair value primarily represents changes due to the realization of cash flows.
	2	Other changes includes purchase price adjustments, principally contractual prepayment protection.
	The following table presents the components of net servicing loss for the three and nine months ended September 30, 2014 (dollars in thousands):
			For the Three Months Ended September 30, 2014			For the Nine Months Ended September 30, 2014
	Servicing fee income		$	9,247		$	22,572
	Incentive, ancillary and other income		3,834			11,462
	Servicing income		13,081			34,034
	Employee compensation and benefit costs		8,678			25,353
	Facility costs		3,831			10,111
	Realization of cash flows from MSR		1,728			2,830
	Other servicing costs		1,976			6,567
	Servicing expense		16,213			44,861
	Net servicing loss		$	(3,132	)	$	(10,827	)
	Risk Mitigation Activities
	The Company’s acquisitions of MSR expose us to certain risks, including interest rate risk and representation and warranty risk. A significant decline in interest rates could lead to higher-than-expected prepayments that could reduce the value of the MSR. Our primary method of managing the prepayment risk associated with our MSR portfolio is asset selection, both in respect of products and the originators of the underlying loans. Representation and warranty risk refers to the representations and warranties we make (or are deemed to have made) to the applicable investor (including, without limitation, the GSEs) regarding, among other things, the origination and servicing of mortgage loans with respect to which we have acquired MSR. We mitigate representation and warranty risk through our due diligence in connection with MSR acquisitions, including counterparty reviews and loan file reviews, as well as negotiated contractual protections from our MSR transaction counterparties with respect to origination and prior servicing.

Other_Assets_Notes

Other Assets (Notes)	9 Months Ended
	Sep. 30, 2014
Other Assets [Abstract]	'
Other Assets Disclosure [Text Block]	'
	Other Assets
	The following table summarizes our other assets as of September 30, 2014 and December 31, 2013 (dollars in thousands):
			September 30, 2014 (1)			December 31, 2013 (1)
	Property and equipment, at cost		$	4,784		$	4,024
	Accumulated depreciation		(1,474		)	(164		)
	Net property and equipment		3,310			3,860
	Servicing advances		16,138			33,358
	Prepaid expenses		5,468			6,978
	Intangible assets		15,000			17,000
	Other		5,722			4,387
	Total other assets		$	45,638		$	65,583
	————————
	-1	Certain amounts within other assets relate to our acquisition of RCS and were recorded at fair value as of the transaction date on a provisional basis and subject to change as the Company finalizes its valuation.
	Servicing Advances
	We are required to fund cash advances in connection with our servicing operations. These servicing advances are reported within other assets on the consolidated balance sheets and represent advances for principal and interest, property taxes and insurance, as well as certain out-of-pocket expenses incurred by the Company in the performance of its servicing obligations.
	Intangible Assets
	During the second quarter of 2014, we sold a portion of RCS' operations for total proceeds of $2.0 million, which was
	accounted for as a reduction of our goodwill.

Other_Liabilities_Notes

Other Liabilities (Notes)	9 Months Ended
	Sep. 30, 2014
Other Liabilities [Abstract]	'
Other Liabilities Disclosure [Text Block]	'
	Accounts Payable and Other Accrued Liabilities
	The following table summarizes our accounts payable and other accrued liabilities as of September 30, 2014 and December 31, 2013 (dollars in thousands):
			September 30, 2014		31-Dec-13
	Cash collateral held on derivatives		$	4,468	$	32,463
	Due to manager		1,849		1,885
	Swaption premium payable		520		—
	Payable for equity securities purchased		—		4,581
	Payable for MSR purchased		4,559		—
	Accrued interest		7,859		4,401
	Mortgage servicing financing, at fair value (1)		14,470		15,608
	Excise tax payable		350		574
	Other accounts payable and accrued expenses		11,349		10,203
	Total accounts payable and other accrued liabilities		$	45,424	$	69,715
	——————
	-1	Mortgage servicing financing represents our obligations associated with excess MSR transferred to a third party which are accounted for as financing arrangements. We have elected the option to account for MSR financing at estimated fair value with changes in fair value reported in net income.

Stockholders_Equity_Notes

Stockholder's Equity (Notes)	9 Months Ended
	Sep. 30, 2014
Stockholders' Equity Attributable to Parent [Abstract]	'
Stockholders' Equity Note Disclosure [Text Block]	'
	Stockholders’ Equity
	Preferred Stock Offering
	Pursuant to our charter, we are authorized to designate and issue up to 50.0 million shares of preferred stock in one or more classes or series. Our Board of Directors has designated 2.3 million shares as 8.125% Series A Cumulative Redeemable Preferred Stock ("Series A Preferred Stock"). As of September 30, 2014, we have 47.8 million of authorized but unissued shares of preferred stock. Our Board of Directors may designate additional series of authorized preferred stock ranking junior to or in parity with the Series A Preferred Stock or designate additional shares of the Series A Preferred Stock and authorize the issuance of such shares.
	In May 2014, we completed a public offering in which 2.2 million shares of our Series A Preferred Stock were sold to the underwriters at a price of $24.2125 per share. Upon completion of the offering we received proceeds, net of offering expenses, of approximately $53.0 million. Our Series A Preferred Stock has no stated maturity and is not subject to any sinking fund or mandatory redemption. Under certain circumstances upon a change of control, the Series A Preferred Stock is convertible to shares of our common stock. Holders of Series A Preferred Stock have no voting rights, except under limited conditions, and holders are entitled to receive cumulative cash dividends at a rate of 8.125% per annum of the $25.00 per share liquidation preference before holders of our common stock are entitled to receive any dividends. Shares of our Series A Preferred Stock are redeemable at $25.00 per share plus accumulated and unpaid dividends (whether or not declared) exclusively at our option commencing on May 22, 2019, or earlier under certain circumstances intended to preserve our qualification as a REIT for Federal income tax purposes. Dividends are payable quarterly in arrears on the 15th day of each January, April, July and October. As of September 30, 2014, we had declared all required quarterly dividends on the Series A Preferred Stock.
	Stock Repurchase Program
	In October 2012, our Board of Directors adopted a program that provided for stock repurchases of up to $50 million of our outstanding shares of common stock through December 31, 2013. In June 2013, our Board of Directors authorized the repurchase of up to an additional $100 million of our outstanding shares of common stock through December 31, 2013. In September 2013, our Board of Directors authorized the repurchase of up to an additional $150 million of our outstanding shares of common stock and extended its authorization through December 31, 2014. In October 2014, our Board of Directors extended the Company's existing stock repurchase program through December 31, 2015.
	We did not repurchase any shares of our common stock during the three months ended September 30, 2014. During the nine months ended September 30, 2014, we repurchased approximately 0.2 million shares of our common stock at an average repurchase price of $19.67 per share, including expenses, totaling $4.2 million. As of September 30, 2014, we had an additional $134.9 million available for repurchases of our common stock through December 31, 2015, as authorized by the Board of Directors.
	Dividend Reinvestment and Direct Stock Purchase Plan
	We sponsor a dividend reinvestment and direct stock purchase plan through which stockholders may purchase additional shares of our common stock by reinvesting some or all of the cash dividends received on shares of our common stock. Stockholders may also make optional cash purchases of shares of our common stock subject to certain limitations detailed in the plan prospectus. We did not issue any shares under the plan during the three and nine months ended September 30, 2014.

Policies

(Policies)	9 Months Ended
	Sep. 30, 2014
Fair Value of Financial Assets [Abstract]	'
Fair Value of Financial Instruments, Policy [Policy Text Block]	'
	Fair Value of Financial Assets
	We have elected the option to account for all of our financial assets, including all mortgage-related investments, at estimated fair value, with changes in fair value reflected in income during the period in which they occur. In management's view, this election more appropriately reflects the results of our operations for a particular reporting period, as financial asset fair value changes are presented in a manner consistent with the presentation and timing of the fair value changes of hedging instruments. See Note 9 - Fair Value Measurements.
Revenue Recognition, Policy [Policy Text Block]	'
	Interest Income
	Interest income is accrued based on the outstanding principal amount of the securities and their contractual terms. Premiums or discounts associated with the purchase of agency RMBS and non-agency RMBS of high credit quality are amortized or accreted into interest income, respectively, over the projected lives of the securities, including contractual payments and estimated prepayments, using the effective interest method.
	We estimate long-term prepayment speeds using a third-party service and market data. The third-party service estimates prepayment speeds for our securities using models that incorporate the mortgage rates, age, size and loan-to-value ratios of the outstanding underlying loans, as well as current mortgage rates, forward yield curves, volatility and other factors. We review the prepayment speeds estimated by the third-party service and compare the results to market consensus prepayment speeds, if available. We also consider historical prepayment speeds and current market conditions to validate the reasonableness of the prepayment speeds estimated by the third-party service, and based on our Manager’s judgment, we may make adjustments to its estimates. Actual and anticipated prepayment experience is reviewed at least quarterly and effective yields are recalculated when differences arise between the previously estimated future prepayments and the amounts actually received plus currently anticipated future prepayments. If the actual and anticipated future prepayment experience differs from our prior estimate of prepayments, we are required to record an adjustment in the current period to the amortization or accretion of premiums and discounts for the cumulative difference in the effective yield through the reporting date.
	At the time we purchase non-agency RMBS and loans that are not of high credit quality, we determine an effective yield based on our estimate of the timing and amount of future cash flows and our cost basis. Our initial cash flow estimates for these investments are based on our observations of current information and events and include assumptions related to interest rates, prepayment rates and the impact of default and severity rates on the timing and amount of credit losses. On at least a quarterly basis, we review the estimated cash flows and make appropriate adjustments, based on input and analysis received from external sources, internal models, and our judgment about interest rates, prepayment rates, the timing and amount of credit losses, and other factors. Any resulting changes in effective yield are recognized prospectively based on the current amortized cost of the investment as adjusted for credit impairment, if any.
Transfers and Servicing of Financial Assets, Servicing of Financial Assets, Policy [Policy Text Block]	'
	Mortgage Servicing Rights, at Fair Value
	Our MSR represent the right to service mortgage loans for a servicing fee. MSR are reported at fair value on our consolidated balance sheets, with changes in fair value related to changes in valuation inputs and assumptions reported as unrealized loss on MSR on the consolidated statements of operations. Servicing fees, incentive fees and ancillary income are reported within servicing income on the consolidated statements of operations. The related servicing expenses and realization of cash flows related to underlying loan repayments, net of recoveries of contractual prepayment protection, are recorded in servicing expenses on the consolidated statements of operations. See Note 10 - Mortgage Servicing Rights for further discussion on MSR.
	The accounting model used to evaluate whether a transfer of MSR qualifies as a sale is based on a risks and rewards approach, as MSR are not financial assets. In certain cases where we transfer the economics of MSR while retaining the actual servicing function, we retain the risk associated with servicing and, as a result, the transfer does not qualify for sale accounting. As such, we retain the MSR, together with an offsetting financing liability on our consolidated balance sheets. We have elected the option to account for MSR financing liabilities at estimated fair value, with changes in fair value reflected in income during the period in which they occur. See Note 12 - Accounts Payable and Other Accrued Liabilities for the presentations of our mortgage servicing liability.
	We may be obligated to fund advances of principal and interest payments due to third party owners of the loans but not yet received from the individual borrowers. We may also be obligated to fund advances of real estate taxes and insurance, protective advances to preserve the value of the underlying property, and expenses associated with remedial action in respect of defaulted loans. These servicing advances are reported within other assets on the consolidated balance sheets.
Marketable Securities, Policy [Policy Text Block]	'
	REIT Equity Securities, at Fair Value
	REIT equity securities represent investments in the common stock of other publicly traded mortgage REITs that invest predominately in agency RMBS. We designate our investments in REIT equity securities as trading securities and report them at fair value on the accompanying consolidated balance sheets with changes in fair value recorded in unrealized gain (loss) on other derivatives and securities, net on the accompanying consolidated statements of operations. Dividend income from REIT equity securities is recorded in realized gain on other derivatives and securities, net.
Repurchase Agreements, Valuation, Policy [Policy Text Block]	'
	Repurchase Agreements
	We finance the acquisition of agency RMBS and certain non-agency RMBS for our investment portfolio through repurchase transactions under master repurchase agreements. We account for repurchase transactions as collateralized financing transactions which are carried at their contractual amounts, including accrued interest, as specified in the respective transaction agreements. The contractual amounts approximate fair value due to their short-term nature.
Repurchase and Resale Agreements Policy [Policy Text Block]	'
	Reverse Repurchase Agreements and Obligation to Return Securities Borrowed under Reverse Repurchase Agreements
	From time to time we borrow securities to cover short sales of U.S. Treasury securities through reverse repurchase transactions under our master repurchase agreements (see Derivatives below). We account for these as securities borrowing transactions and recognize an obligation to return the borrowed securities at fair value on the consolidated balance sheets based on the value of the underlying borrowed securities as of the reporting date. Our reverse repurchase agreements generally mature daily. The fair value of our reverse repurchase agreements is assumed to equal cost as the interest rates are reset daily.
Derivatives, Policy [Policy Text Block]	'
	Derivatives
	We utilize a risk management strategy, under which we may use a variety of derivative instruments to hedge some of our exposure to market risks, including interest rate risk, prepayment risk, extension risk and credit risk. The objective of our risk management strategy is to reduce fluctuations in net book value over a range of market conditions. The principal instruments that we currently use are interest rate swaps and options to enter into interest rate swaps ("interest rate swaptions"). We also utilize forward contracts for the purchase or sale of agency RMBS, or to-be-announced forward ("TBA") contracts, and short sales of U.S. Treasury securities and U.S. Treasury futures contracts. We may also purchase or write put or call options on TBA securities and we may invest in other types of mortgage derivatives, such as synthetic total return swaps.
	We also enter into TBA contracts as a means of investing in and financing agency RMBS (thereby increasing our "at
	risk" leverage) or as a means of disposing of or reducing our exposure to agency RMBS (thereby reducing our "at risk" leverage). Pursuant to TBA contracts, we agree to purchase or sell, for future delivery, agency RMBS with certain principal and interest terms and certain types of collateral, but the particular agency RMBS to be delivered are not identified until shortly before the TBA settlement date. We may also choose, prior to settlement, to move the settlement of these securities out to a later date by entering into an offsetting short or long position (referred to as a "pair off"), net settling the paired off positions for cash, and simultaneously purchasing or selling a similar TBA contract for a later settlement date. This transaction is commonly referred to as a "dollar roll." The agency RMBS purchased or sold for a forward settlement date are typically priced at a discount to agency RMBS for settlement in the current month. This difference (or discount) is referred to as the "price drop." The price drop is the economic equivalent of net interest carry income on the underlying agency RMBS over the roll period (interest income less implied financing cost) and is commonly referred to as "dollar roll income (loss)." Consequently, forward purchases of agency RMBS and dollar roll transactions represent a form of off-balance sheet financing.
	We recognize all derivative instruments as either assets or liabilities on the balance sheets, measured at fair value. As we have not designated any derivatives as hedging instruments, all changes in fair value are reported in earnings in our consolidated statements of operations in unrealized gain (loss) on other derivatives and securities, net during the period in which they occur. Derivatives in a gain position are reported as derivative assets at fair value and derivatives in a loss position are reported as derivative liabilities at fair value in our consolidated balance sheets. Cash receipts and payments related to derivative instruments are classified in our consolidated statements of cash flows according to the underlying nature or purpose of the derivative transaction, generally in the investing section.
	Our derivative agreements generally contain provisions that allow for netting or setting off derivative assets and liabilities with each counterparty; however, we report related assets and liabilities on a gross basis in our consolidated balance sheets.
	The use of derivatives creates exposure to credit risk relating to potential losses that could be recognized in the event that the counterparties to these instruments fail to perform their obligations under the contracts. We attempt to minimize this risk by limiting our counterparties to major financial institutions with acceptable credit ratings, monitoring positions with individual counterparties and adjusting posted collateral as required.
	Interest rate swap agreements
	We use interest rate swaps to hedge the variable cash flows associated with short-term borrowings made under our repurchase agreement facilities. Under our interest rate swap agreements, we typically pay a fixed rate and receive a floating rate based on one, three or six-month LIBOR ("payer swaps") with terms up to 15 years. The floating rate we receive under our swap agreements has the effect of offsetting the repricing characteristics of our repurchase agreements and cash flows on such liabilities. Our swap agreements are privately negotiated in the over-the-counter ("OTC") market and may be centrally cleared through a registered commodities exchange ("centrally cleared swaps").
	We estimate the fair value of our centrally cleared interest rate swaps using the daily settlement price determined by the respective exchange. Centrally cleared swaps are valued by the exchange using a pricing model that references the underlying rates, including the overnight index swap rate and LIBOR forward rate, to produce the daily settlement price. We estimate the fair value of our "non-centrally cleared" swaps using a combination of inputs from counterparty and third-party pricing models to estimate the net present value of the future cash flows using a forward yield curve in effect as of the end of the measurement period. We also incorporate any of our own and our counterparties’ unmitigated nonperformance risk in estimating the fair value of our interest rate swaps. In considering the effect of nonperformance risk, we consider the impact of netting and credit enhancements, such as collateral postings and guarantees, and have concluded that our own and our counterparty credit risk is not significant to the overall valuation of these agreements.
	The payment of periodic settlements of net interest on interest rate swaps is reported in realized loss on periodic settlements of interest rate swaps, net in our consolidated statements of operations. Cash payments received or paid for the early termination of an interest rate swap agreement are recorded as realized gain on other derivatives and securities, net in our consolidated statements of operations. Changes in fair value of our interest rate swap agreements are reported in unrealized gain (loss) on other derivatives and securities, net in our consolidated statements of operations.
	Interest rate swaptions
	We purchase interest rate swaptions to help mitigate the potential impact of larger increases or decreases in interest rates
	on the performance of our investment portfolio. The interest rate swaptions provide us the option to enter into an interest rate swap agreement for a predetermined notional amount, stated term and pay or receive interest rates in the future. The premium paid for interest rate swaptions is reported as a derivative asset in our consolidated balance sheets. We estimate the fair value of interest rate swaptions based on the fair value of the future interest rate swap that we have the option to enter into as well as the remaining length of time that we have to exercise the option. The difference between the premium and the fair value of the swaption is reported in unrealized gain (loss) on other derivatives and securities, net in our consolidated statements of operations. If a swaption expires unexercised, the realized loss on the swaption would be equal to the premium paid and reported in realized gain on other derivatives and securities, net in our consolidated statements of operations. If we exercise a swaption, the realized gain or loss on the swaption would be equal to the difference between the fair value of the underlying interest rate swap and the premium paid and reported in realized gain on other derivatives and securities, net in our consolidated statements of operations.
	Interest rate swaption agreements are privately negotiated in the OTC market and are not subject to central clearing. We estimate the fair value of interest rate swaptions using a combination of inputs from counterparty and third-party pricing models based on the fair value of the future interest rate swap that we have the option to enter into as well as the remaining length of time that we have to exercise the option, adjusted for non-performance risk, if any.
	TBA securities
	A TBA security is a forward contract for the purchase ("long position") or sale ("short position") of agency RMBS at a predetermined price, face amount, issuer, coupon and stated maturity on an agreed-upon future date. The specific agency RMBS delivered into the contract upon the settlement date, published each month by the Securities Industry and Financial Markets Association, are not known at the time of the transaction. We may enter into TBA contracts as a means of hedging against short-term changes in interest rates. We may also enter into TBA contracts as a means of acquiring or disposing of agency RMBS and we may from time to time utilize TBA dollar roll transactions to finance agency RMBS purchases.
	We account for all TBA contracts as derivatives since we cannot assert that it is probable at the inception and throughout the term of the contract that it will not settle net and will result in physical delivery of an agency security when it is issued. A TBA dollar roll transaction is a series of derivative transactions. The net settlement of a TBA contract is reported as realized gain on other derivatives and securities, net and changes in the fair value of our TBA contracts are reported as unrealized gain (loss) on other derivatives and securities, net in our consolidated statements of operations.
	We estimate the fair value of TBA securities based on similar methods used to value our agency RMBS.
	Forward commitments to purchase or sell specified securities
	We may enter into a forward commitment to purchase or sell specified securities as a means of acquiring assets or as a hedge against short-term changes in interest rates. Such forward commitments usually require physical settlement. Contracts for the purchase or sale of specified securities are accounted for as derivatives if the delivery of the specified agency RMBS and settlement extends beyond established market conventions. Realized gains and losses associated with forward commitments are recognized in realized gain on other derivatives and securities, net and unrealized gains and losses are recognized in unrealized gain (loss) on other derivatives and securities, net on our consolidated statements of operations.
	We estimate the fair value of forward commitments to purchase or sell specified RMBS based on methods used to value our RMBS, as well as the remaining length of time of the forward commitment.
	U.S. Treasury securities
	We purchase or sell short U.S. Treasury securities and U.S. Treasury futures contracts to help mitigate the potential impact of changes in interest rates on the performance of our portfolio. Realized gains and losses associated with purchases and short sales of U.S. Treasury securities and U.S. Treasury futures contracts are recognized in realized gain on other derivatives and securities, net, and unrealized gains and losses are recognized in unrealized gain (loss) on other derivatives and securities, net on our consolidated statements of operations.

Agency_Securities_Tables

Agency Securities (Tables)	9 Months Ended
	Sep. 30, 2014
Agency Securities [Abstract]	'
Agency Securities [Table Text Block]	'
	The following tables summarize our investments in agency RMBS as of September 30, 2014 and December 31, 2013 (dollars in thousands):
		September 30, 2014
		Fannie Mae				Freddie Mac				Ginnie Mae				Total
	Agency RMBS:
	Par value	$	3,356,063			$	772,754			$	—			$	4,128,817
	Unamortized premium	143,203				38,808				—				182,011
	Amortized cost	3,499,266				811,562				—				4,310,828
	Gross unrealized gains	12,351				3,715				—				16,066
	Gross unrealized losses	(54,226		)		(12,905		)		—				(67,131		)
	Agency RMBS, at fair value	$	3,457,391			$	802,372			$	—			$	4,259,763
	Weighted average coupon as of September 30, 2014	3.37		%		3.5		%		—		%		3.39		%
	Weighted average yield as of September 30, 2014	2.56		%		2.69		%		—		%		2.59		%
	Weighted average yield for the three months ended September 30, 2014	2.49		%		2.61		%		—		%		2.52		%
	Weighted average yield for the nine months ended September 30, 2014	2.5		%		2.61		%		2.12		%		2.52		%
			September 30, 2014
			Amortized Cost				Gross Unrealized Gain				Gross Unrealized Loss				Fair Value
	Agency RMBS:
	Fixed rate		$	4,185,822			$	13,567			$	(67,131	)		$	4,132,258
	Adjustable rate		125,006				2,499				—				127,505
	Total		$	4,310,828			$	16,066			$	(67,131	)		$	4,259,763
		31-Dec-13
		Fannie Mae				Freddie Mac				Ginnie Mae				Total
	Fixed-rate agency RMBS:
	Par value	$	4,461,621			$	1,079,180			$	32,792			$	5,573,593
	Unamortized premium	195,633				50,265				703				246,601
	Amortized cost	4,657,254				1,129,445				33,495				5,820,194
	Gross unrealized gains	4,230				1,570				568				6,368
	Gross unrealized losses	(150,447		)		(34,433		)		—				(184,880		)
	Fixed-rate agency RMBS, at fair value	$	4,511,037			$	1,096,582			$	34,063			$	5,641,682
	Weighted average coupon as of December 31, 2013	3.33		%		3.44		%		3		%		3.35		%
	Weighted average yield as of December 31, 2013	2.53		%		2.67		%		2.12		%		2.56		%
	Weighted average yield for the year ended December 31, 2013	2.69		%		2.87		%		2.22		%		2.72		%
			31-Dec-13
			Amortized Cost				Gross Unrealized Gain				Gross Unrealized Loss				Fair Value
	Agency RMBS:
	Fixed rate		$	5,358,579			$	3,678			$	(184,565	)		$	5,177,692
	Adjustable rate		461,615				2,690				(315		)		463,990
	Total		$	5,820,194			$	6,368			$	(184,880	)		$	5,641,682
Summary Of Agency Securities Estimated Weighted Average Life Classifications Text Block	'
	The following table summarizes our agency RMBS as of September 30, 2014 and December 31, 2013 according to their estimated weighted average life classification (dollars in thousands):
		September 30, 2014														December 31, 2013
										Weighted Average												Weighted Average
	Weighted Average Life	Fair				Amortized				Yield			Coupon			Fair			Amortized			Yield		Coupon
		Value				Cost										Value			Cost
	Less than or equal to three years	$	—			$	—			—	%		—	%		$	9,089		$	9,095		2.38	%	3.49	%
	Greater than three years and less than or equal to five years	1,457,026				1,462,276				2.14	%		3.08	%		2,142,111			2,159,311			2.29	%	3.2	%
	Greater than five years and less than or equal to 10 years	2,763,147				2,808,772				2.81	%		3.55	%		3,485,241			3,646,188			2.72	%	3.43	%
	Greater than 10 years	39,590				39,780				3.19	%		3.64	%		5,241			5,600			2.96	%	3.5	%
	Total	$	4,259,763			$	4,310,828			2.59	%		3.39	%		$	5,641,682		$	5,820,194		2.56	%	3.35	%
Schedule of Realized Gain (Loss) [Table Text Block]	'
	The following table summarizes our net realized gains and losses from the sale of agency RMBS during the three and nine months ended September 30, 2014 and 2013 (dollars in thousands):
			For the Three Months Ended September 30,								For the Nine Months Ended September 30,
			2014				2013				2014				2013
	Proceeds from agency RMBS sold		$	400,042			$	2,076,462			$	2,067,118			$	5,356,680
	Increase (decrease) in receivable for agency RMBS sold		(77,918		)		39,397				(570,029		)		201,968
	Less agency RMBS sold, at cost		(321,439		)		(2,187,038		)		(1,505,485		)		(5,642,132		)
	Net realized gain (loss) on sale of agency RMBS		$	685			$	(71,179	)		$	(8,396	)		$	(83,484	)
	Gross realized gains on sale of agency RMBS		$	1,552			$	241			$	9,382			$	18,965
	Gross realized losses on sale of agency RMBS		(867		)		(71,420		)		(17,778		)		(102,449		)
	Net realized gain (loss) on sale of agency RMBS		$	685			$	(71,179	)		$	(8,396	)		$	(83,484	)
	The following table summarizes our net realized gains and losses from the sale of non-agency RMBS during the three and nine months ended September 30, 2014 and 2013 (dollars in thousands):
			For the Three Months Ended September 30,								For the Nine Months Ended September 30,
			2014				2013				2014				2013
	Proceeds from non-agency RMBS sold		$	166,204			$	41,026			$	461,415			$	160,405
	Increase (decrease) in receivable for non-agency RMBS sold		10,514				—				10,514				—
	Less: non-agency RMBS sold, at cost		(159,315		)		(35,142		)		(440,134		)		(144,795		)
	Net realized gain on sale of non-agency RMBS		$	17,403			$	5,884			$	31,795			$	15,610
	Gross realized gain on sale of non-agency RMBS		$	18,436			$	6,836			$	36,731			$	17,543
	Gross realized loss on sale of non-agency RMBS		(1,033		)		(952		)		(4,936		)		(1,933		)
	Net realized gain on sale of non-agency RMBS		$	17,403			$	5,884			$	31,795			$	15,610
Schedule of Financial Instruments Owned and Pledged as Collateral [Table Text Block]	'
	The following tables summarize our agency RMBS pledged as collateral under repurchase agreements and derivative agreements by type as of September 30, 2014 and December 31, 2013 (dollars in thousands):
			September 30, 2014
	Agency RMBS Pledged		Fannie Mae				Freddie Mac				Total
	Under Repurchase Agreements (1)
	Fair value		$	2,448,137			$	1,608,806			$	4,056,943
	Accrued interest on pledged agency RMBS		6,688				4,378				11,066
	Under Derivative Agreements
	Fair value		631				—				631
	Accrued interest on pledged agency RMBS		2				—				2
	Total Fair Value of Agency RMBS Pledged and Accrued Interest		$	2,455,458			$	1,613,184			$	4,068,642
			31-Dec-13
	Agency RMBS Pledged		Fannie Mae				Freddie Mac				Ginnie Mae				Total
	Under Repurchase Agreements
	Fair value		$	4,492,566			$	1,092,106			$	34,063			$	5,618,735
	Accrued interest on pledged agency RMBS		12,287				3,078				82				15,447
	Total Fair Value of Agency RMBS Pledged and Accrued Interest		$	4,504,853			$	1,095,184			$	34,145			$	5,634,182
	————————
	-1	Agency RMBS pledged do not include $14.9 million pledged under repurchase agreements related to securities sold but not yet settled as of September 30, 2014.
Schedules Of Securities Pledged As Collateral Under Repurchase Agreement [Text Block] [Table Text Block]	'
	The following table summarizes our agency RMBS pledged as collateral under repurchase agreements by remaining maturity as of September 30, 2014 and December 31, 2013 (dollars in thousands):
			September 30, 2014												December 31, 2013
	Remaining Maturity		Fair Value				Amortized				Accrued Interest				Fair Value			Amortized			Accrued Interest
							Cost											Cost
	30 days or less		$	1,643,365			$	1,659,527			$	4,609			$	2,591,560		$	2,672,502		$	7,182
	31 - 59 days		731,888				736,700				1,880				1,105,167			1,151,447			3,096
	60 - 90 days		545,575				554,329				1,463				1,261,354			1,299,749			3,455
	Greater than 90 days		1,136,115				1,155,824				3,114				660,654			673,560			1,714
	Total		$	4,056,943			$	4,106,380			$	11,066			$	5,618,735		$	5,797,258		$	15,447
	The following table summarizes our non-agency RMBS pledged as collateral under repurchase agreements by remaining maturity as of September 30, 2014 and December 31, 2013 (dollars in thousands):
			September 30, 2014												December 31, 2013
	Remaining Maturity		Fair Value				Amortized				Accrued Interest				Fair Value			Amortized			Accrued Interest
							Cost											Cost
	30 days or less		$	701,439			$	649,382			$	998			$	547,087		$	502,063		$	857
	31 - 59 days		90,035				79,064				66				70,478			68,622			57
	60 - 90 days		38,367				34,275				41				64,873			58,091			55
	Greater than 90 days		16,020				16,799				11				216,738			196,644			242
	Total		$	845,861			$	779,520			$	1,116			$	899,176		$	825,420		$	1,211
	————————
	-1	Non-agency RMBS pledged do not include $10.5 million pledged under repurchase agreements related to securities sold but not yet settled as of September 30, 2014.

NonAgency_Securities_Tables

Non-Agency Securities (Tables)	9 Months Ended
	Sep. 30, 2014
Schedule of Available-for-sale Securities [Line Items]	'
Non-Agency Securities [Table Text Block]	'
	The following tables summarize our non-agency RMBS as of September 30, 2014 and December 31, 2013 (dollars in thousands):
	September 30, 2014
			Fair			Gross Unrealized							Amortized Cost				Discount				Par/ Current Face				Weighted Average
	Category		Value			Gains			Losses																Coupon (1)			Yield
	Prime (2)		$	257,128		$	16,569		$	(3,126	)		$	243,685			$	(213,015	)		$	456,700			2.29	%		6.56	%
	Alt-A		494,564			42,923			(3,512		)		455,153				(178,394		)		633,547				1.65	%		6.99	%
	Option-ARM		168,928			13,123			(1,430		)		157,235				(43,095		)		200,330				0.49	%		6.25	%
	Subprime		155,247			8,817			(533		)		146,963				(39,711		)		186,674				1.64	%		5.51	%
	Total		$	1,075,867		$	81,432		$	(8,601	)		$	1,003,036			$	(474,215	)		$	1,477,251			1.69	%		6.55	%
	————————
	-1	Coupon rates are floating, except for $2.7 million, $30.2 million and $50.0 million fair value of fixed-rate prime, Alt-A and subprime non-agency RMBS, respectively, as of September 30, 2014.
	(2)	Prime non-agency RMBS include GSE credit risk transfer securities with $69.2 million in fair value and interest only investments with a fair value of $12.4 million and a current face value of $198.3 million as of September 30, 2014.
	31-Dec-13
			Fair			Gross Unrealized							Amortized Cost				Discount				Par/ Current Face				Weighted Average
	Category		Value			Gains			Losses																Coupon (1)			Yield
	Prime (2)		$	195,524		$	14,161		$	(5,658	)		$	187,021			$	(222,436	)		$	409,457			2	%		6.13	%
	Alt-A		467,531			46,311			(3,420		)		424,640				(199,407		)		624,047				1.56	%		7.6	%
	Option-ARM		119,054			14,809			(1,650		)		105,895				(45,367		)		151,262				0.54	%		7.4	%
	Subprime		229,108			21,471			(1,938		)		209,575				(132,577		)		342,152				1.01	%		6.69	%
	Total		$	1,011,217		$	96,752		$	(12,666	)		$	927,131			$	(599,787	)		$	1,526,918			1.46	%		7.07	%
	————————
	-1	Coupon rates are floating, except for $67.4 million, $16.6 million and $51.9 million fair value of fixed-rate prime, Alt-A and subprime non-agency RMBS, respectively, as of December 31, 2013.
	(2)	Prime non-agency RMBS include GSE credit risk transfer securities with $5.3 million in fair value and interest only investments with a fair value of $11.0 million and a current face value of $206.4 million as of December 31, 2013.
Schedule of Non-Agency Securities by Weighted Average Life [Table Text Block]	'
	The following table summarizes our non-agency RMBS at fair value, by their estimated weighted average life classifications as of September 30, 2014 and December 31, 2013 (dollars in thousands):
			September 30, 2014												31-Dec-13
	Weighted Average Life		Fair Value			Amortized			Weighted			Weighted Average Coupon			Fair Value				Amortized				Weighted			Weighted Average Coupon
						Cost			Average										Cost				Average
									Yield														Yield
	≤ 5 years		$	360,644		$	342,486		6.06	%		2.53	%		$	203,935			$	194,800			5.59	%		2.19	%
	> 5 to ≤ 7 years		434,783			395,342			7.1	%		1.31	%		211,013				195,913				6.84	%		2.38	%
	>7 years		280,440			265,208			6.36	%		1.45	%		596,269				536,418				7.7	%		1.08	%
	Total		$	1,075,867		$	1,003,036		6.55	%		1.69	%		$	1,011,217			$	927,131			7.07	%		1.46	%
Realized Gain (Loss) on Investments [Table Text Block]	'
	The following table summarizes our net realized gains and losses from the sale of agency RMBS during the three and nine months ended September 30, 2014 and 2013 (dollars in thousands):
			For the Three Months Ended September 30,						For the Nine Months Ended September 30,
			2014			2013			2014				2013
	Proceeds from agency RMBS sold		$	400,042		$	2,076,462		$	2,067,118			$	5,356,680
	Increase (decrease) in receivable for agency RMBS sold		(77,918		)	39,397			(570,029		)		201,968
	Less agency RMBS sold, at cost		(321,439		)	(2,187,038		)	(1,505,485		)		(5,642,132		)
	Net realized gain (loss) on sale of agency RMBS		$	685		$	(71,179	)	$	(8,396	)		$	(83,484	)
	Gross realized gains on sale of agency RMBS		$	1,552		$	241		$	9,382			$	18,965
	Gross realized losses on sale of agency RMBS		(867		)	(71,420		)	(17,778		)		(102,449		)
	Net realized gain (loss) on sale of agency RMBS		$	685		$	(71,179	)	$	(8,396	)		$	(83,484	)
	The following table summarizes our net realized gains and losses from the sale of non-agency RMBS during the three and nine months ended September 30, 2014 and 2013 (dollars in thousands):
			For the Three Months Ended September 30,						For the Nine Months Ended September 30,
			2014			2013			2014				2013
	Proceeds from non-agency RMBS sold		$	166,204		$	41,026		$	461,415			$	160,405
	Increase (decrease) in receivable for non-agency RMBS sold		10,514			—			10,514				—
	Less: non-agency RMBS sold, at cost		(159,315		)	(35,142		)	(440,134		)		(144,795		)
	Net realized gain on sale of non-agency RMBS		$	17,403		$	5,884		$	31,795			$	15,610
	Gross realized gain on sale of non-agency RMBS		$	18,436		$	6,836		$	36,731			$	17,543
	Gross realized loss on sale of non-agency RMBS		(1,033		)	(952		)	(4,936		)		(1,933		)
	Net realized gain on sale of non-agency RMBS		$	17,403		$	5,884		$	31,795			$	15,610
Schedules Of Securities Pledged As Collateral Under Repurchase Agreement [Text Block] [Table Text Block]	'
	The following table summarizes our agency RMBS pledged as collateral under repurchase agreements by remaining maturity as of September 30, 2014 and December 31, 2013 (dollars in thousands):
			September 30, 2014										December 31, 2013
	Remaining Maturity		Fair Value			Amortized			Accrued Interest				Fair Value				Amortized				Accrued Interest
						Cost											Cost
	30 days or less		$	1,643,365		$	1,659,527		$	4,609			$	2,591,560			$	2,672,502			$	7,182
	31 - 59 days		731,888			736,700			1,880				1,105,167				1,151,447				3,096
	60 - 90 days		545,575			554,329			1,463				1,261,354				1,299,749				3,455
	Greater than 90 days		1,136,115			1,155,824			3,114				660,654				673,560				1,714
	Total		$	4,056,943		$	4,106,380		$	11,066			$	5,618,735			$	5,797,258			$	15,447
	The following table summarizes our non-agency RMBS pledged as collateral under repurchase agreements by remaining maturity as of September 30, 2014 and December 31, 2013 (dollars in thousands):
			September 30, 2014										December 31, 2013
	Remaining Maturity		Fair Value			Amortized			Accrued Interest				Fair Value				Amortized				Accrued Interest
						Cost											Cost
	30 days or less		$	701,439		$	649,382		$	998			$	547,087			$	502,063			$	857
	31 - 59 days		90,035			79,064			66				70,478				68,622				57
	60 - 90 days		38,367			34,275			41				64,873				58,091				55
	Greater than 90 days		16,020			16,799			11				216,738				196,644				242
	Total		$	845,861		$	779,520		$	1,116			$	899,176			$	825,420			$	1,211
	————————
	-1	Non-agency RMBS pledged do not include $10.5 million pledged under repurchase agreements related to securities sold but not yet settled as of September 30, 2014.

Repurchase_Agreements_Tables

Repurchase Agreements (Tables)	9 Months Ended
	Sep. 30, 2014
Disclosure of Repurchase Agreements [Abstract]	'
Schedule of Debt [Table Text Block]	'
	At September 30, 2014 and December 31, 2013, our borrowings under repurchase agreements had the following collateral characteristics (dollars in thousands):
		September 30, 2014					December 31, 2013
				Weighted Average					Weighted Average
	Collateral Type	Borrowings		Interest Rate		Days	Borrowings		Interest Rate		Days
		Outstanding				to Maturity	Outstanding				to Maturity
	Agency securities	$	3,814,485	0.39	%	99	$	5,935,610	0.43	%	96
	Non-agency securities	646,793		1.7	%	22	647,068		1.79	%	33
	Treasury securities	460,534		0.02	%	7	575,514		0.07	%	2
	Total repurchase agreements	$	4,921,812	0.52	%	80	$	7,158,192	0.52	%	83
	The following table summarizes our borrowings under repurchase arrangements and weighted average interest rates classified by remaining maturities as of September 30, 2014 and December 31, 2013 (dollars in thousands):
		September 30, 2014					December 31, 2013
				Weighted Average					Weighted Average
		Borrowings		Interest Rate		Days	Borrowings		Interest Rate		Days
		Outstanding				to Maturity	Outstanding				to Maturity
	Agency and non-agency repurchase agreements
	≤ 1 month	$	2,113,444	0.67	%	12	$	3,047,986	0.6	%	14
	> 1 to ≤ 2 months	797,223		0.51	%	50	816,960		0.55	%	45
	> 2 to ≤ 3 months	569,354		0.44	%	77	1,506,888		0.52	%	77
	> 3 to ≤ 6 months	401,830		0.48	%	137	621,124		0.54	%	135
	> 6 to ≤ 9 months	305,480		0.47	%	242	147,729		0.49	%	249
	> 9 to ≤ 12 months	23,947		0.48	%	290	191,991		0.5	%	321
	> 12 months	250,000		0.59	%	580	250,000		0.59	%	853
	Total	4,461,278		0.58	%	87	6,582,678		0.56	%	90
	U.S. Treasury repurchase agreements
	Short-term	460,534		0.02	%	7	575,514		0.07	%	2
	Total repurchase agreements	$	4,921,812	0.52	%	80	$	7,158,192	0.52	%	83

Derivatives_Tables

Derivatives (Tables)	9 Months Ended
	Sep. 30, 2014
Derivative [Line Items]	'
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block]	'
	The table below presents the balance sheet location and fair value information for our derivatives outstanding as of September 30, 2014 and December 31, 2013 (in thousands):
			30-Sep-14				31-Dec-13
	Interest rate swaps		$	20,480			$	51,957
	Interest rate swaptions		7,603				50,009
	U.S. Treasury futures		1,196				3,399
	TBA securities		3,662				2,856
	Mortgage options		7				—
	Derivative assets, at fair value		$	32,948			$	108,221
	Interest rate swaps		$	42,950			$	9,490
	TBA securities		5,730				1,837
	Mortgage options		62				—
	Derivative liabilities, at fair value		$	48,742			$	11,327
Schedule of Derivative Instruments, Gain (Loss) in Statement of Financial Performance [Table Text Block]	'
	The following tables summarize the effect of our outstanding derivatives and other securities on our consolidated statements of operations during the three and nine months ended September 30, 2014 and 2013 (in thousands):
			For the Three Months Ended September 30,
			2014										2013
			Realized Loss on Periodic Settlements of Interest Rate Swaps, net			Realized Gain on Other Derivatives and Securities, net			Unrealized Gain (Loss) on Other Derivatives and Securities, net				Realized Loss on Periodic Settlements of Interest Rate Swaps, net			Realized Gain on Other Derivatives and Securities, net			Unrealized Gain (Loss) on Other Derivatives and Securities, net
	Interest rate swaps		$	(5,226	)	$	—		$	13,445			$	(14,449	)	$	53,365		$	(53,588	)
	Interest rate swaptions		—			(719		)	(514		)		—			18,625			(32,498		)
	TBA securities		—			16,840			(15,004		)		—			(42,505		)	3,433
	U.S. Treasuries		—			(222		)	(145		)		—			(12,716		)	18,140
	U.S. Treasury futures		—			(653		)	559				—			6,650			(9,930		)
	Short sales of U.S. Treasuries		—			(2,964		)	(377		)		—			41,839			(30,695		)
	REIT equity investments		—			1,188			(1,375		)		—			—			—
	Mortgage options		—			234			108				—			—			—
	Total		$	(5,226	)	$	13,704		$	(3,303	)		$	(14,449	)	$	65,258		$	(105,138	)
			For the Nine Months Ended September 30,
			2014										2013
			Realized Loss on Periodic Settlements of Interest Rate Swaps, net			Realized Gain on Other Derivatives and Securities, net			Unrealized Gain (Loss) on Other Derivatives and Securities, net				Realized Loss on Periodic Settlements of Interest Rate Swaps, net			Realized Gain on Other Derivatives and Securities, net			Unrealized Gain (Loss) on Other Derivatives and Securities, net
	Interest rate swaps		$	(15,400	)	$	68		$	(64,757	)		$	(32,228	)	$	53,365		$	123,930
	Interest rate swaptions		—			(17,551		)	(8,882		)		—			15,193			11,398
	TBA securities		—			22,832			(3,086		)		—			(23,119		)	(50,095		)
	U.S. Treasuries		—			2,536			12,293				—			(13,786		)	7,489
	U.S. Treasury futures		—			(4,630		)	(2,202		)		—			9,353			(2,743		)
	Short sales of U.S. Treasuries		—			(8,928		)	(5,444		)		—			45,669			2,939
	REIT equity investments					8,675			502				—			—			—
	Mortgage options		—			234			(32		)					—			—
	Total		$	(15,400	)	$	3,236		$	(71,608	)		$	(32,228	)	$	86,675		$	92,918
Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block]	'
	The following tables summarize changes in notional amounts for our outstanding derivatives and other securities for the nine months ended September 30, 2014 and 2013 (in thousands):
		31-Dec-13				Additions/ Long Positions			Expirations/			30-Sep-14
		Notional							Terminations/ Short Positions			Notional
		Amount										Amount
	Interest rate swaps	$	3,240,000			875,000			(150,000	)		$	3,965,000
	Interest rate swaptions	$	2,100,000			275,000			(1,900,000	)		$	475,000
	TBA securities	$	(773,816	)		15,525,174			(13,834,986	)		$	916,372
	U.S. Treasuries	$	656,000			832,570			(1,016,570	)		$	472,000
	U.S. Treasury futures	$	(150,000	)		450,000			(450,000	)		$	(150,000	)
	Short sales of U.S. Treasuries	$	(23,000	)		1,085,500			(1,797,000	)		$	(734,500	)
	Mortgage options	$	—			100,000			(200,000	)		$	(100,000	)
		31-Dec-12				Additions/ Long Positions			Expirations/			30-Sep-13
		Notional							Terminations/ Short Positions			Notional
		Amount										Amount
	Interest rate swaps	$	2,940,000			2,900,000			(1,450,000	)		$	4,390,000
	Interest rate swaptions	$	1,150,000			2,150,000			(1,100,000	)		$	2,200,000
	TBA securities	$	(522,188	)		7,109,859			(8,195,521	)		$	(1,607,850	)
	U.S. Treasuries	$	—			3,865,000			(3,005,000	)		$	860,000
	U.S. Treasury futures	$	—			500,000			(650,000	)		$	(150,000	)
	Short sales of U.S. Treasuries	$	(425,000	)		3,200,000			(2,775,000	)		$	—
Schedule Of Interest Rate Swap Agreement By Remaining Maturity [Table Text Block]	'
	As of September 30, 2014 and December 31, 2013, we had interest rate swap agreements summarized in the tables below (dollars in thousands).
					30-Sep-14								31-Dec-13
	Interest Rate Swaps		Balance Sheet Location		Notional Amount				Fair Value				Notional Amount				Fair Value
	Interest rate swap assets		Derivative assets, at fair value		$	1,350,000			$	20,480			$	2,275,000			$	51,957
	Interest rate swap liabilities		Derivative liabilities, at fair value		2,615,000				(42,950		)		965,000				(9,490		)
					$	3,965,000			$	(22,470	)		$	3,240,000			$	42,467
	September 30, 2014
			Notional				Fair Value				Weighted Average
			Amount
	Current Maturity Date for Interest Rate Swaps (1)										Fixed			Receive			Maturity
											Pay Rate (2)			Rate (3)			(Years)
	≤ 3 years		$	840,000			$	(5,339	)		1.04	%		0.23	%		1.5
	> 3 to ≤ 5 years		1,075,000				7,454				1.58	%		0.23	%		4
	> 5 to ≤ 7 years		1,050,000				(3,235		)		2.44	%		0.23	%		5.8
	> 7 years		1,000,000				(21,350		)		3.16	%		0.23	%		8.2
	Total		$	3,965,000			$	(22,470	)		2.09	%		0.23	%		5
	December 31, 2013
			Notional				Fair Value				Weighted Average
	Current Maturity Date for Interest Rate Swaps (4)		Amount								Fixed			Receive			Maturity
											Pay Rate (2)			Rate (3)			(Years)
	≤ 3 years		$	650,000			$	(6,612	)		0.87	%		0.24	%		1.4
	> 3 to ≤ 5 years		815,000				4,722				1.11	%		0.24	%		3.9
	> 5 to ≤ 7 years		1,025,000				21,434				2.28	%		0.24	%		6.4
	> 7 years		750,000				22,923				3.12	%		0.24	%		9.1
	Total		$	3,240,000			$	42,467			1.9	%		0.24	%		5.4
	————————
	(1)	Includes swaps with an aggregate notional of $1.9 billion with deferred start dates averaging 1.2 years from September 30, 2014.
	(2)	Excluding forward starting swaps, the weighted average pay rate was 1.25% and 1.18% as of September 30, 2014 and December 31, 2013, respectively.
	(3)	Weighted average receive rate excludes impact of forward starting interest rate swaps.
	(4)	Includes swaps with an aggregate notional of $1.2 billion with deferred start dates averaging 1.9 years from December 31, 2013.
Schedule of Interest Rate Swaption Agreements Outstandin [Table Text Block]	'
	The following tables present certain information about our interest rate swaption agreements as of September 30, 2014 and December 31, 2013 (dollars in thousands):
	September 30, 2014
			Option										Underlying Swap
	Current Option Expiration Date		Cost				Fair Value				Weighted Average Years to Expiration		Notional Amount				Pay Rate			Weighted Average Term (Years)
	≤ 3 months		$	179			$	88			0		$	50,000			1.3	%		3
	> 3 to ≤ 12 months		4,765				2,835				0.7		100,000				3.34	%		7
	>12 to ≤ 24 months		1,308				635				1.5		100,000				4.13	%		7
	> 24 months		3,946				4,045				2.7		225,000				2.97	%		3.7
	Total / weighted average		$	10,198			$	7,603			1.8		$	475,000			3.11	%		5
	December 31, 2013
			Option										Underlying Swap
	Current Option Expiration Date		Cost				Fair Value				Weighted Average Years to Expiration		Notional Amount				Pay Rate			Weighted Average Term (Years)
	≤ 3 months		$	17,015			$	19,841			0.1		$	925,000			2.59	%		8
	> 3 to ≤ 12 months		13,868				10,406				0.6		550,000				2.94	%		8.2
	>12 to ≤ 24 months		8,105				8,979				1.7		400,000				3.63	%		6.3
	> 24 months		4,734				10,783				3.2		225,000				3.62	%		5.9
	Total / weighted average		$	43,722			$	50,009			0.9		$	2,100,000			2.99	%		7.5
Schedule of Long and Short Position of Derivative Instruments [Table Text Block]	'
	TBA Securities
	As of September 30, 2014 and December 31, 2013, we had contracts to purchase ("long position") and sell ("short position") TBA securities on a forward basis, presented in the following table (in thousands):
			30-Sep-14								31-Dec-13
	Purchase and Sale Contracts for TBA Securities		Notional				Fair				Notional				Fair
			Amount (1)				Value (2)				Amount (1)				Value (2)
	TBA assets
	Purchase of TBA securities		$	1,005,970			$	3,449			$	210,600			$	158
	Sale of TBA securities		(100,578		)		213				(463,496		)		2,698
	Total TBA assets		905,392				3,662				(252,896		)		2,856
	TBA liabilities
	Purchase of TBA securities		433,080				(3,808		)		—				—
	Sale of TBA securities		(422,100		)		(1,922		)		(520,920		)		(1,837		)
	Total TBA liabilities		10,980				(5,730		)		(520,920		)		(1,837		)
	Total net TBA		$	916,372			$	(2,068	)		$	(773,816	)		$	1,019
	————————
	(1)	Notional amount represents the par value or principal balance of the underlying agency security.
	(2)	Fair value represents the current market value of the agency RMBS underlying the TBA contract as of period end, less the forward price to be paid for the underlying agency RMBS.

Offsetting_Assets_and_Liabilit1

Offsetting Assets and Liabilities Offsetting Financial and Derivative Assets (Tables)	9 Months Ended
	Sep. 30, 2014
Offsetting of Financial Assets and Derivative Assets [Abstract]	'
Offsetting Liabilities [Table Text Block]	'
	Offsetting of Financial Liabilities and Derivative Liabilities:
		Gross Amounts of Recognized Liabilities		Gross Amounts Offset in the Consolidated Balance Sheets		Net Amounts Presented		Gross Amounts Not Offset in the Consolidated Balance Sheets
						in the Consolidated Balance Sheets		Financial Instruments			Collateral Pledged (2)			Net Amount
	September 30, 2014
	Interest rate swaps (1)	$	42,950	$	—	$	42,950	$	(6,288	)	$	(36,662	)	$	—
	Repurchase agreements	4,921,812		—		4,921,812		(566,887		)	(4,354,925		)	—
	Total	$	4,964,762	$	—	$	4,964,762	$	(573,175	)	$	(4,391,587	)	$	—
	December 31, 2013
	Interest rate swaps (1)	$	9,490	$	—	$	9,490	$	(9,490	)	$	—		$	—
	Repurchase agreements	7,158,192		—		7,158,192		(22,736		)	(7,135,456		)	—
	Total	$	7,167,682	$	—	$	7,167,682	$	(32,226	)	$	(7,135,456	)	$	—
Offsetting Assets [Table Text Block]	'
	Offsetting of Financial Assets and Derivative Assets:
		Gross Amounts of Recognized Assets		Gross Amounts Offset in the Consolidated Balance Sheets		Net Amounts Presented		Gross Amounts Not Offset in the Consolidated Balance Sheets
						in the Consolidated Balance Sheets		Financial Instruments			Collateral Received (2)			Net Amount
	September 30, 2014
	Interest rate swaps and swaptions (1)	$	28,083	$	—	$	28,083	$	(6,288	)	$	(8,205	)	$	13,590
	Receivable under reverse repurchase agreements	745,443		—		745,443		(566,887		)	(176,990		)	1,566
	Total	$	773,526	$	—	$	773,526	$	(573,175	)	$	(185,195	)	$	15,156
	December 31, 2013
	Interest rate swaps and swaptions (1)	$	101,966	$	—	$	101,966	$	(9,490	)	$	(45,084	)	$	47,392
	Receivable under reverse repurchase agreements	22,736		—		22,736		(22,736		)	—			—
	Total	$	124,702	$	—	$	124,702	$	(32,226	)	$	(45,084	)	$	47,392

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2014
Fair Value Disclosures [Abstract]	'
Fair Value, Assets Measured on Recurring Basis [Table Text Block]	'
	The following tables present our financial instruments carried at fair value as of September 30, 2014 and December 31, 2013, on the consolidated balance sheets by the valuation hierarchy, as described above (in thousands):
			September 30, 2014
			Level 1			Level 2			Level 3			Total
	Assets
	Agency RMBS		$	—		$	4,259,763		$	—		$	4,259,763
	Non-agency RMBS		—			1,075,867			—			1,075,867
	U.S. Treasury securities		467,201			—			—			467,201
	Derivative assets		—			32,948			—			32,948
	MSR assets		—			—			100,314			100,314
	Total		$	467,201		$	5,368,578		$	100,314		$	5,936,093
	Liabilities
	Derivative liabilities		$	—		$	48,742		$	—		$	48,742
	Obligation to return securities borrowed under reverse repurchase agreements		742,642			—			—			742,642
	MSR financing liabilities		—			—			14,470			14,470
	Total		$	742,642		$	48,742		$	14,470		$	805,854
			December 31, 2013
			Level 1			Level 2			Level 3			Total
	Assets
	Agency RMBS		$	—		$	5,641,682		$	—		$	5,641,682
	Non-agency RMBS		—			1,011,217			—			1,011,217
	REIT equity securities		38,807			—			—			38,807
	U.S. Treasury securities		637,342			—			—			637,342
	Derivative assets		—			108,221			—			108,221
	MSR assets		—			—			15,608			15,608
	Total		$	676,149		$	6,761,120		$	15,608		$	7,452,877
	Liabilities
	Derivative liabilities		$	—		$	11,327		$	—		$	11,327
	Obligation to return securities borrowed under reverse repurchase agreements		22,530			—			—			22,530
	MSR financing liabilities		—			—			15,608			15,608
	Total		$	22,530		$	11,327		$	15,608		$	49,465
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]	'
	The following table presents a summary of the changes in fair value for Level 3 assets carried at fair value as of September 30, 2014 (in thousands):
			For the Nine Months Ended September 30, 2014
			MSR Under Secured Financing (1)			Purchased MSR			Total MSR
	Balance as of December 31, 2013		$	15,608		$	—		$	15,608
	Gains/(losses) included in net income:
	Realized gains (losses)		(968		)	(2,830		)	(3,798		)
	Unrealized gains (losses)		(170		)	(3,705		)	(3,875		)
	Total net gains/(losses) included in net income		(1,138		)	(6,535		)	(7,673		)
	Purchases, net of purchase price adjustments		—			92,379			92,379
	Balance as of September 30, 2014		$	14,470		$	85,844		$	100,314
	————————
	-1	Gains (losses) included in net income related to MSR under secured financing are offset in their entirety by (losses) gains associated with related MSR financing liabilities.
	We use third-party pricing providers in the fair value measurement of our Level 3 MSR. The significant unobservable inputs used in estimating the fair value measurement of our Level 3 MSR assets and financing liabilities include assumptions for underlying loan constant prepayment rates and delinquency rates, as well as discount rates. We review the various third-party fair value estimates used to determine the fair value of our MSR and perform procedures to validate their reasonableness. In reviewing the estimated fair values of our Level 3 MSR, we use internal models and our own estimates of prepayment and
	delinquency rates on the loans underlying our MSR.
Fair Value Inputs, Assets, Quantitative Information [Table Text Block]	'
	The following table presents the range of our estimates of loan constant voluntary prepayment rates and constant default rates, together with the discount rates used by third-party pricing providers in estimating the fair value of our Level 3 MSR as of September 30, 2014 (dollars in thousands):
			September 30, 2014
	Unobservable Level 3 Input		Fair Value			Minimum		Weighted	Maximum
								Average
	MSR treated as financing arrangements:		$	14,470
	Constant prepayment rate					9.70%		14.70%	34.50%
	Constant default rate					—%		7.40%	28.20%
	Discount rate					16.00%		16.00%	16.00%
	Purchased MSR:		85,844
	Constant prepayment rate					7.30%		7.70%	8.10%
	Constant default rate					0.20%		0.30%	0.40%
	Discount rate					8.30%		8.70%	9.30%
	Total		$	100,314

Mortgage_Servicing_Rights_Tabl

Mortgage Servicing Rights (Tables)	9 Months Ended
	Sep. 30, 2014
Servicing Assets at Fair Value [Line Items]	'
Schedule of Servicing Assets at Fair Value [Table Text Block]	'
	The following table summarizes activity related to MSR accounted for as purchases during the nine months ended September 30, 2014 (dollars in thousands):
		For the Nine Months Ended September 30, 2014
	Balance as of December 31, 2013	$	—
	Additions from purchases of MSR	93,414
	Changes in fair value due to:
	Changes in valuation inputs or assumptions used in valuation model	(3,705		)
	Other changes in fair value (1)	(2,830		)
	Other changes (2)	(1,035		)
	Balance as of September 30, 2014	$	85,844
Other Income and Other Expense Disclosure [Text Block]	'
	The following table presents the components of net servicing loss for the three and nine months ended September 30, 2014 (dollars in thousands):
		For the Three Months Ended September 30, 2014			For the Nine Months Ended September 30, 2014
	Servicing fee income	$	9,247		$	22,572
	Incentive, ancillary and other income	3,834			11,462
	Servicing income	13,081			34,034
	Employee compensation and benefit costs	8,678			25,353
	Facility costs	3,831			10,111
	Realization of cash flows from MSR	1,728			2,830
	Other servicing costs	1,976			6,567
	Servicing expense	16,213			44,861
	Net servicing loss	$	(3,132	)	$	(10,827	)

Other_Assets_Tables

Other Assets (Tables)	9 Months Ended
	Sep. 30, 2014
Other Assets [Abstract]	'
Schedule of Other Assets [Table Text Block]	'
	The following table summarizes our other assets as of September 30, 2014 and December 31, 2013 (dollars in thousands):
		September 30, 2014 (1)			December 31, 2013 (1)
	Property and equipment, at cost	$	4,784		$	4,024
	Accumulated depreciation	(1,474		)	(164		)
	Net property and equipment	3,310			3,860
	Servicing advances	16,138			33,358
	Prepaid expenses	5,468			6,978
	Intangible assets	15,000			17,000
	Other	5,722			4,387
	Total other assets	$	45,638		$	65,583

Other_Liabilities_Tables

Other Liabilities (Tables)	9 Months Ended
	Sep. 30, 2014
Other Liabilities [Abstract]	'
Other Liabilities [Table Text Block]	'
	The following table summarizes our accounts payable and other accrued liabilities as of September 30, 2014 and December 31, 2013 (dollars in thousands):
		September 30, 2014		31-Dec-13
	Cash collateral held on derivatives	$	4,468	$	32,463
	Due to manager	1,849		1,885
	Swaption premium payable	520		—
	Payable for equity securities purchased	—		4,581
	Payable for MSR purchased	4,559		—
	Accrued interest	7,859		4,401
	Mortgage servicing financing, at fair value (1)	14,470		15,608
	Excise tax payable	350		574
	Other accounts payable and accrued expenses	11,349		10,203
	Total accounts payable and other accrued liabilities	$	45,424	$	69,715

Agency_Securities_Agency_Secur

Agency Securities Agency Securities (Narrative) (Details)	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
WeightedAverageLifeofAgencySecurities	'7 years 1 month	'6 years 1 month 0 days
Weighted Average Expected CPR Over Remaining Life of Agency Portfolio	8.00%	7.00%
Minimum [Member]	'	'
WeightedAverageLifeofAgencySecurities	'3 years 5 months	'2 years 1 month 15 days

Recovered_Sheet1

Agency Securities Agency securities, at fair value (Details) (USD $)	3 Months Ended	9 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2014	Dec. 31, 2013
Schedule of Agency Securities [Line Items]	'	'	'
Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value	$4,259,763	$4,259,763	$5,641,682
Agency Securities [Member]	'	'	'
Schedule of Agency Securities [Line Items]	'	'	'
Agency Securities at Par	4,128,817	4,128,817	5,573,593
Agency Securities Unamortized Premium	182,011	182,011	246,601
Agency Securities Amortized Cost	4,310,828	4,310,828	5,820,194
Agency Securities, Gross Unrealized Gains	16,066	16,066	6,368
Agency Securities, Gross Unrealized Losses	-67,131	-67,131	-184,880
Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value	4,259,763	4,259,763	5,641,682
Weighted Average Coupon Rate	3.39%	3.39%	3.35%
Weighted Average Yield Percentage	2.59%	2.59%	2.56%
Weighted Average Yield Percentage for Period	2.52%	2.52%	2.72%
Agency Securities [Member] | Fixed Rate Residential Mortgage [Member]	'	'	'
Schedule of Agency Securities [Line Items]	'	'	'
Agency Securities Amortized Cost	4,185,822	4,185,822	5,358,579
Agency Securities, Gross Unrealized Gains	13,567	13,567	3,678
Agency Securities, Gross Unrealized Losses	-67,131	-67,131	-184,565
Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value	4,132,258	4,132,258	5,177,692
Agency Securities [Member] | Adjustable Rate Residential Mortgage [Member]	'	'	'
Schedule of Agency Securities [Line Items]	'	'	'
Agency Securities Amortized Cost	125,006	125,006	461,615
Agency Securities, Gross Unrealized Gains	2,499	2,499	2,690
Agency Securities, Gross Unrealized Losses	0	0	-315
Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value	127,505	127,505	463,990
Agency Securities [Member] | Fannie Mae [Member]	'	'	'
Schedule of Agency Securities [Line Items]	'	'	'
Agency Securities at Par	3,356,063	3,356,063	4,461,621
Agency Securities Unamortized Premium	143,203	143,203	195,633
Agency Securities Amortized Cost	3,499,266	3,499,266	4,657,254
Agency Securities, Gross Unrealized Gains	12,351	12,351	4,230
Agency Securities, Gross Unrealized Losses	-54,226	-54,226	-150,447
Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value	3,457,391	3,457,391	4,511,037
Weighted Average Coupon Rate	3.37%	3.37%	3.33%
Weighted Average Yield Percentage	2.56%	2.56%	2.53%
Weighted Average Yield Percentage for Period	2.49%	2.50%	2.69%
Agency Securities [Member] | Freddie Mac [Member]	'	'	'
Schedule of Agency Securities [Line Items]	'	'	'
Agency Securities at Par	772,754	772,754	1,079,180
Agency Securities Unamortized Premium	38,808	38,808	50,265
Agency Securities Amortized Cost	811,562	811,562	1,129,445
Agency Securities, Gross Unrealized Gains	3,715	3,715	1,570
Agency Securities, Gross Unrealized Losses	-12,905	-12,905	-34,433
Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value	802,372	802,372	1,096,582
Weighted Average Coupon Rate	3.50%	3.50%	3.44%
Weighted Average Yield Percentage	2.69%	2.69%	2.67%
Weighted Average Yield Percentage for Period	2.61%	2.61%	2.87%
Agency Securities [Member] | Ginnie Mae [Member]	'	'	'
Schedule of Agency Securities [Line Items]	'	'	'
Agency Securities at Par	0	0	32,792
Agency Securities Unamortized Premium	0	0	703
Agency Securities Amortized Cost	0	0	33,495
Agency Securities, Gross Unrealized Gains	0	0	568
Agency Securities, Gross Unrealized Losses	0	0	0
Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value	$0	$0	$34,063
Weighted Average Coupon Rate	0.00%	0.00%	3.00%
Weighted Average Yield Percentage	0.00%	0.00%	2.12%
Weighted Average Yield Percentage for Period	0.00%	2.12%	2.22%

Agency_Securities_Weighted_Ave

Agency Securities Weighted Average Life of Agency Securities (Details) (USD $)	9 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value	$4,259,763	$5,641,682
WeightedAverageLifeofAgencySecurities	'7 years 1 month	'6 years 1 month 0 days
Prepayment Rate Of Remaining Life Of Investment Portfolio	8.00%	7.00%
Agency Securities [Member]	'	'
Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value	4,259,763	5,641,682
Agency Securities Amortized Cost	4,310,828	5,820,194
Weighted Average Yield Percentage	2.59%	2.56%
Weighted Average Coupon Rate	3.39%	3.35%
Agency Securities [Member] | Less Than Three Years [Domain]	'	'
Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value	0	9,089
Agency Securities Amortized Cost	0	9,095
Weighted Average Yield Percentage	0.00%	2.38%
Weighted Average Coupon Rate	0.00%	3.49%
Agency Securities [Member] | Greater Than Three Years and Less Than or Equal to Five Years [Member]	'	'
Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value	1,457,026	2,142,111
Agency Securities Amortized Cost	1,462,276	2,159,311
Weighted Average Yield Percentage	2.14%	2.29%
Weighted Average Coupon Rate	3.08%	3.20%
Agency Securities [Member] | Greater than 5 years and less than or equal to 10 years [Member]	'	'
Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value	2,763,147	3,485,241
Agency Securities Amortized Cost	2,808,772	3,646,188
Weighted Average Yield Percentage	2.81%	2.72%
Weighted Average Coupon Rate	3.55%	3.43%
Agency Securities [Member] | Greater than 10 years [Member]	'	'
Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value	39,590	5,241
Agency Securities Amortized Cost	$39,780	$5,600
Weighted Average Yield Percentage	3.19%	2.96%
Weighted Average Coupon Rate	3.64%	3.50%
Minimum [Member]	'	'
WeightedAverageLifeofAgencySecurities	'3 years 5 months	'2 years 1 month 15 days

Agency_Securities_Realized_Gai

Agency Securities Realized Gains and Losses on Agency Securities (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Schedule of Agency Securities [Line Items]	'	'	'	'	'
Proceeds from Sale of Agency Securities, Debt	$400,042	$2,076,462	$2,067,118	$5,356,680	'
Increase (Decrease) in Other Receivables	-77,918	39,397	-570,029	201,968	'
Cost of Sale of Agency Securities	-321,439	-2,187,038	-1,505,485	-5,642,132	'
Gain (Loss) on Sales of Mortgage Backed Securities (MBS)	685	-71,179	-8,396	-83,484	'
Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value	4,259,763	'	4,259,763	'	5,641,682
Agency Securities [Member]	'	'	'	'	'
Schedule of Agency Securities [Line Items]	'	'	'	'	'
Agency Securities Amortized Cost	4,310,828	'	4,310,828	'	5,820,194
Agency Securities, Gross Realized Gains	1,552	241	9,382	18,965	'
Agency Securities, Gross Realized Losses	-867	-71,420	-17,778	-102,449	'
Gain (Loss) on Sales of Mortgage Backed Securities (MBS)	685	-71,179	-8,396	-83,484	'
Agency Securities, Gross Unrealized Gains	16,066	'	16,066	'	6,368
Agency Securities, Gross Unrealized Losses	-67,131	'	-67,131	'	-184,880
Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value	4,259,763	'	4,259,763	'	5,641,682
Fixed Rate Residential Mortgage [Member] | Agency Securities [Member]	'	'	'	'	'
Schedule of Agency Securities [Line Items]	'	'	'	'	'
Agency Securities Amortized Cost	4,185,822	'	4,185,822	'	5,358,579
Agency Securities, Gross Unrealized Gains	13,567	'	13,567	'	3,678
Agency Securities, Gross Unrealized Losses	-67,131	'	-67,131	'	-184,565
Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value	4,132,258	'	4,132,258	'	5,177,692
Adjustable Rate Residential Mortgage [Member] | Agency Securities [Member]	'	'	'	'	'
Schedule of Agency Securities [Line Items]	'	'	'	'	'
Agency Securities Amortized Cost	125,006	'	125,006	'	461,615
Agency Securities, Gross Unrealized Gains	2,499	'	2,499	'	2,690
Agency Securities, Gross Unrealized Losses	0	'	0	'	-315
Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value	$127,505	'	$127,505	'	$463,990

Agency_Securities_Agency_Secur1

Agency Securities Agency Securities Pledged Under Borrowing Agreements (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Total Fair Value Of Agency Securities Pledged And Accrued Interest	$4,068,642,000	$5,634,182,000
Fannie Mae [Member]	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Total Fair Value Of Agency Securities Pledged And Accrued Interest	2,455,458,000	4,504,853,000
Freddie Mac [Member]	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Total Fair Value Of Agency Securities Pledged And Accrued Interest	1,613,184,000	1,095,184,000
Ginnie Mae [Member]	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Total Fair Value Of Agency Securities Pledged And Accrued Interest	'	82,000
Agency Securities [Member]	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Agency Securities Pledged As Collateral	4,057,574,000	5,618,735,000
Repurchase Agreements [Member] | Agency Securities [Member]	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Agency Securities Pledged As Collateral	4,056,943,000	5,618,735,000
Agency Securities Pledged As Collateral Amortized Cost	4,106,380,000	5,797,258,000
Agency Securities Pledged As Collateral Accrued Interest	11,066,000	15,447,000
Repurchase Agreements [Member] | Agency Securities [Member] | Fannie Mae [Member]	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Agency Securities Pledged As Collateral	2,448,137,000	4,492,566,000
Agency Securities Pledged As Collateral Accrued Interest	6,688,000	12,287,000
Repurchase Agreements [Member] | Agency Securities [Member] | Freddie Mac [Member]	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Agency Securities Pledged As Collateral	1,608,806,000	1,092,106,000
Agency Securities Pledged As Collateral Accrued Interest	4,378,000	3,078,000
Repurchase Agreements [Member] | Agency Securities [Member] | Ginnie Mae [Member]	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Agency Securities Pledged As Collateral	'	34,063,000
Under Derivative Agreements [Member] | Agency Securities [Member]	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Agency Securities Pledged As Collateral	631,000	'
Agency Securities Pledged As Collateral Accrued Interest	2,000	'
Under Derivative Agreements [Member] | Agency Securities [Member] | Fannie Mae [Member]	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Agency Securities Pledged As Collateral	631,000	'
Agency Securities Pledged As Collateral Accrued Interest	2,000	'
Under Derivative Agreements [Member] | Agency Securities [Member] | Freddie Mac [Member]	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Agency Securities Pledged As Collateral	0	'
Agency Securities Pledged As Collateral Accrued Interest	0	'
Agency Securities [Member]	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Collateralized Agency Securities Sold But Not Settled	$14,900,000	'

Agency_Securities_Agency_Secur2

Agency Securities Agency Securities Pledged As Collateral by Maturity Date (Details) (Agency Securities [Member], USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Agency Securities Pledged As Collateral	$4,057,574	$5,618,735
Repurchase Agreements [Member]	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Agency Securities Pledged As Collateral	4,056,943	5,618,735
Agency Securities Pledged As Collateral Amortized Cost	4,106,380	5,797,258
Pledged Assets, Not Separately Reported, Other	11,066	15,447
Repurchase Agreements [Member] | Maturity up to 30 days [Member]	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Agency Securities Pledged As Collateral	1,643,365	2,591,560
Agency Securities Pledged As Collateral Amortized Cost	1,659,527	2,672,502
Pledged Assets, Not Separately Reported, Other	4,609	7,182
Repurchase Agreements [Member] | Maturity 31 To 59 Days [Member]	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Agency Securities Pledged As Collateral	731,888	1,105,167
Agency Securities Pledged As Collateral Amortized Cost	736,700	1,151,447
Pledged Assets, Not Separately Reported, Other	1,880	3,096
Repurchase Agreements [Member] | Maturity 60 To 90 Days [Member]	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Agency Securities Pledged As Collateral	545,575	1,261,354
Agency Securities Pledged As Collateral Amortized Cost	554,329	1,299,749
Pledged Assets, Not Separately Reported, Other	1,463	3,455
Repurchase Agreements [Member] | Maturity over 90 days [Member]	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Agency Securities Pledged As Collateral	1,136,115	660,654
Agency Securities Pledged As Collateral Amortized Cost	1,155,824	673,560
Pledged Assets, Not Separately Reported, Other	$3,114	$1,714

NonAgency_Securities_Schedule_

Non-Agency Securities Schedule of Non-Agency Securities (Details) (USD $)	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Narrative [Abstract]	'	'
Non-Agency Securities, at Fair Value	$1,075,867,000	$1,011,217,000
Prime [Member]	'	'
Non-Agency Security, at Fair Value	257,128,000	195,524,000
Gross Unrealized Gain on Non-Agency Securities	16,569,000	14,161,000
Gross Unrealized Loss on Non-Agency Securities	-3,126,000	-5,658,000
Non-Agency Securities, at Amortized Cost	243,685,000	187,021,000
Debt Instrument, Unamortized Discount	-213,015,000	-222,436,000
Non-Agency Securities at Par	456,700,000	409,457,000
Weighted Average Coupon Rate	2.29%	2.00%
Weighted Average Yield Percentage	6.56%	6.13%
Narrative [Abstract]	'	'
Fixed Rate Non-Agency Security	2,700,000	67,400,000
Concentration Risk, Credit Risk, Financial Instruments	'69172	'5321
Prime [Member] | Interest-Only-Strip [Member]	'	'
Non-Agency Securities at Par	198,300,000	206,400,000
Narrative [Abstract]	'	'
Non-Agency Securities, at Fair Value	12,400,000	11,000,000
Alt-A [Member]	'	'
Non-Agency Security, at Fair Value	494,564,000	467,531,000
Gross Unrealized Gain on Non-Agency Securities	42,923,000	46,311,000
Gross Unrealized Loss on Non-Agency Securities	-3,512,000	-3,420,000
Non-Agency Securities, at Amortized Cost	455,153,000	424,640,000
Debt Instrument, Unamortized Discount	-178,394,000	-199,407,000
Non-Agency Securities at Par	633,547,000	624,047,000
Weighted Average Coupon Rate	1.65%	1.56%
Weighted Average Yield Percentage	6.99%	7.60%
Narrative [Abstract]	'	'
Fixed Rate Non-Agency Security	30,200,000	16,600,000
Option-Arm [Member]	'	'
Non-Agency Security, at Fair Value	168,928,000	119,054,000
Gross Unrealized Gain on Non-Agency Securities	13,123,000	14,809,000
Gross Unrealized Loss on Non-Agency Securities	-1,430,000	-1,650,000
Non-Agency Securities, at Amortized Cost	157,235,000	105,895,000
Debt Instrument, Unamortized Discount	-43,095,000	-45,367,000
Non-Agency Securities at Par	200,330,000	151,262,000
Weighted Average Coupon Rate	0.49%	0.54%
Weighted Average Yield Percentage	6.25%	7.40%
Subprime [Member]	'	'
Non-Agency Security, at Fair Value	155,247,000	229,108,000
Gross Unrealized Gain on Non-Agency Securities	8,817,000	21,471,000
Gross Unrealized Loss on Non-Agency Securities	-533,000	-1,938,000
Non-Agency Securities, at Amortized Cost	146,963,000	209,575,000
Debt Instrument, Unamortized Discount	-39,711,000	-132,577,000
Non-Agency Securities at Par	186,674,000	342,152,000
Weighted Average Coupon Rate	1.64%	1.01%
Weighted Average Yield Percentage	5.51%	6.69%
Narrative [Abstract]	'	'
Fixed Rate Non-Agency Security	50,000,000	51,900,000
Non-Agency Securities [Member]	'	'
Non-Agency Security, at Fair Value	1,075,867,000	1,011,217,000
Gross Unrealized Gain on Non-Agency Securities	81,432,000	96,752,000
Gross Unrealized Loss on Non-Agency Securities	-8,601,000	-12,666,000
Non-Agency Securities, at Amortized Cost	1,003,036,000	927,131,000
Debt Instrument, Unamortized Discount	-474,215,000	-599,787,000
Non-Agency Securities at Par	$1,477,251,000	$1,526,918,000
Weighted Average Coupon Rate	1.69%	1.46%
Weighted Average Yield Percentage	6.55%	7.07%
External Credit Rating, Non Investment Grade [Member]	'	'
Percentage of Non-Investment Grade Non-Agency Securities	98.00%	'

NonAgency_Securities_Weighted_

Non-Agency Securities Weighted Average Life of Non-Agency Securities (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Non-Agency Securities, at Fair Value	$1,075,867	$1,011,217
Less Than or Equal to Five Years [Member]	'	'
Non-Agency Security, at Fair Value	360,644	203,935
Non-Agency Securities, at Amortized Cost	342,486	194,800
Weighted Average Yield Percentage	6.06%	5.59%
Weighted Average Coupon Rate	2.53%	2.19%
Greater Than Five Years and Less Than or Equal to Seven Year [Member]	'	'
Non-Agency Security, at Fair Value	434,783	211,013
Non-Agency Securities, at Amortized Cost	395,342	195,913
Weighted Average Yield Percentage	7.10%	6.84%
Weighted Average Coupon Rate	1.31%	2.38%
Greater Than Seven Years [Member]	'	'
Non-Agency Security, at Fair Value	280,440	596,269
Non-Agency Securities, at Amortized Cost	265,208	536,418
Weighted Average Yield Percentage	6.36%	7.70%
Weighted Average Coupon Rate	1.45%	1.08%
Prime [Member]	'	'
Non-Agency Security, at Fair Value	257,128	195,524
Non-Agency Securities, at Amortized Cost	243,685	187,021
Weighted Average Yield Percentage	6.56%	6.13%
Weighted Average Coupon Rate	2.29%	2.00%
Prime [Member] | Pre-2010 [Member]	'	'
Non-Agency Security, at Fair Value	175,600	'
Prime [Member] | 2013 [Member]	'	'
Non-Agency Security, at Fair Value	81,500	'
Prime [Member] | Minimum [Member]	'	'
Weighted Average Coupon Rate	0.75%	'
Underlying Collateral Coupon	2.38%	'
Prime [Member] | Maximum [Member]	'	'
Weighted Average Coupon Rate	6.50%	'
Underlying Collateral Coupon	5.82%	'
Alt-A [Member]	'	'
Non-Agency Security, at Fair Value	494,564	467,531
Non-Agency Securities, at Amortized Cost	455,153	424,640
Weighted Average Yield Percentage	6.99%	7.60%
Weighted Average Coupon Rate	1.65%	1.56%
Alt-A [Member] | Minimum [Member]	'	'
Weighted Average Coupon Rate	0.22%	'
Underlying Collateral Coupon	2.65%	'
Alt-A [Member] | Maximum [Member]	'	'
Weighted Average Coupon Rate	6.50%	'
Underlying Collateral Coupon	6.91%	'
Option-Arm [Member]	'	'
Non-Agency Security, at Fair Value	168,928	119,054
Non-Agency Securities, at Amortized Cost	157,235	105,895
Weighted Average Yield Percentage	6.25%	7.40%
Weighted Average Coupon Rate	0.49%	0.54%
Option-Arm [Member] | Minimum [Member]	'	'
Weighted Average Coupon Rate	0.34%	'
Underlying Collateral Coupon	2.72%	'
Option-Arm [Member] | Maximum [Member]	'	'
Weighted Average Coupon Rate	1.06%	'
Underlying Collateral Coupon	3.53%	'
Subprime [Member]	'	'
Non-Agency Security, at Fair Value	155,247	229,108
Non-Agency Securities, at Amortized Cost	146,963	209,575
Weighted Average Yield Percentage	5.51%	6.69%
Weighted Average Coupon Rate	1.64%	1.01%
Subprime [Member] | 2013 [Member]	'	'
Non-Agency Security, at Fair Value	15,600	'
Subprime [Member] | Pre-2013 [Member]	'	'
Non-Agency Security, at Fair Value	139,600	'
Subprime [Member] | Minimum [Member] | 2013 [Member]	'	'
Weighted Average Coupon Rate	3.25%	'
Underlying Collateral Coupon	5.67%	'
Subprime [Member] | Minimum [Member] | Pre-2013 [Member]	'	'
Weighted Average Coupon Rate	0.21%	'
Underlying Collateral Coupon	4.53%	'
Subprime [Member] | Maximum [Member] | 2013 [Member]	'	'
Weighted Average Coupon Rate	4.25%	'
Underlying Collateral Coupon	8.38%	'
Subprime [Member] | Maximum [Member] | Pre-2013 [Member]	'	'
Weighted Average Coupon Rate	5.37%	'
Underlying Collateral Coupon	7.82%	'
Non-Agency Securities [Member]	'	'
Non-Agency Security, at Fair Value	1,075,867	1,011,217
Non-Agency Securities, at Amortized Cost	$1,003,036	$927,131
Weighted Average Yield Percentage	6.55%	7.07%
Weighted Average Coupon Rate	1.69%	1.46%

NonAgency_Securities_Realized_

Non-Agency Securities Realized Gains (Losses) from Sale of Non-Agency Securities (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Gain (Loss) on Investments [Line Items]	'	'	'	'
Proceeds from sale of non-agency securities	'	'	($461,415)	($160,405)
Increase (Decrease) in Other Receivables	-77,918	39,397	-570,029	201,968
Realized gain on non-agency securities, net	'	'	31,795	15,610
Non-Agency Securities [Member]	'	'	'	'
Gain (Loss) on Investments [Line Items]	'	'	'	'
Proceeds from sale of non-agency securities	166,204	41,026	461,415	160,405
Increase (Decrease) in Other Receivables	10,514	0	10,514	0
Cost of Sale of Non-Agency Securities	-159,315	-35,142	-440,134	-144,795
Available-for-sale Securities, Gross Realized Gains	-18,436	-6,836	-36,731	-17,543
Available-for-sale Securities, Gross Realized Losses	-1,033	-952	-4,936	-1,933
Realized gain on non-agency securities, net	$17,403	$5,884	$31,795	$15,610

NonAgency_Securities_NonAgency

Non-Agency Securities Non-Agency Securities Pledged Under Repurchase Agreements (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
Non-Agency Securities [Member] | Repurchase Agreements [Member]	'	'
Short-term Debt [Line Items]	'	'
Security Owned and Pledged as Collateral, Fair Value	$845,861,000	$899,176,000
Agency Securities Pledged As Collateral Amortized Cost	779,520,000	825,420,000
Pledged Assets, Not Separately Reported, Other	1,116,000	1,211,000
Maturity up to 30 days [Member] | Non-Agency Securities [Member] | Repurchase Agreements [Member]	'	'
Short-term Debt [Line Items]	'	'
Security Owned and Pledged as Collateral, Fair Value	701,439,000	547,087,000
Agency Securities Pledged As Collateral Amortized Cost	649,382,000	502,063,000
Pledged Assets, Not Separately Reported, Other	998,000	857,000
Maturity 31 To 59 Days [Member] | Non-Agency Securities [Member] | Repurchase Agreements [Member]	'	'
Short-term Debt [Line Items]	'	'
Security Owned and Pledged as Collateral, Fair Value	90,035,000	70,478,000
Agency Securities Pledged As Collateral Amortized Cost	79,064,000	68,622,000
Pledged Assets, Not Separately Reported, Other	66,000	57,000
Maturity 60 To 90 Days [Member] | Non-Agency Securities [Member] | Repurchase Agreements [Member]	'	'
Short-term Debt [Line Items]	'	'
Security Owned and Pledged as Collateral, Fair Value	38,367,000	64,873,000
Agency Securities Pledged As Collateral Amortized Cost	34,275,000	58,091,000
Pledged Assets, Not Separately Reported, Other	41,000	55,000
Maturity over 90 days [Member] | Non-Agency Securities [Member] | Repurchase Agreements [Member]	'	'
Short-term Debt [Line Items]	'	'
Security Owned and Pledged as Collateral, Fair Value	16,020,000	216,738,000
Agency Securities Pledged As Collateral Amortized Cost	16,799,000	196,644,000
Pledged Assets, Not Separately Reported, Other	11,000	242,000
Non-Agency Securities [Member]	'	'
Short-term Debt [Line Items]	'	'
Collateralized Agreements	$10,500,000	'

Repurchase_Agreements_Repurcha

Repurchase Agreements Repurchase Agreements by Collateral Type (Details) (USD $)	9 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Short-term Debt [Line Items]	'	'
Securities Sold under Agreements to Repurchase	'	$7,158,192
Short-term Debt, Weighted Average Interest Rate	0.52%	0.52%
Weighted Average Days to Maturity	'80 days	'83 days
Agency Securities [Member]	'	'
Short-term Debt [Line Items]	'	'
Securities Sold under Agreements to Repurchase	3,814,485	5,935,610
Short-term Debt, Weighted Average Interest Rate	0.39%	0.43%
Weighted Average Days to Maturity	'99 days	'96 days
Non-Agency Securities [Member]	'	'
Short-term Debt [Line Items]	'	'
Securities Sold under Agreements to Repurchase	646,793	647,068
Short-term Debt, Weighted Average Interest Rate	1.70%	1.79%
Weighted Average Days to Maturity	'22 days	'33 days
US Treasury Securities [Member]	'	'
Short-term Debt [Line Items]	'	'
Securities Sold under Agreements to Repurchase	$460,534	$575,514
Short-term Debt, Weighted Average Interest Rate	0.02%	0.07%
Weighted Average Days to Maturity	'7 days	'2 days

Repurchase_Agreements_Schedule

Repurchase Agreements Schedule of Repurchase Agreements (Details) (USD $)	9 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Statement [Line Items]	'	'
Securities Sold under Agreements to Repurchase	'	$7,158,192
Short-term Debt, Weighted Average Interest Rate	0.52%	0.52%
Weighted Average Days to Maturity	'80 days	'83 days
Maturity up to 30 days [Member]	'	'
Statement [Line Items]	'	'
Securities Sold under Agreements to Repurchase	2,113,444	3,047,986
Short-term Debt, Weighted Average Interest Rate	0.67%	0.60%
Weighted Average Days to Maturity	'12 days	'14 days
Maturity Thirty One To Sixty Days [Member]	'	'
Statement [Line Items]	'	'
Securities Sold under Agreements to Repurchase	797,223	816,960
Short-term Debt, Weighted Average Interest Rate	0.51%	0.55%
Weighted Average Days to Maturity	'50 days	'45 days
Maturity 61 To 90 Days [Member]	'	'
Statement [Line Items]	'	'
Securities Sold under Agreements to Repurchase	569,354	1,506,888
Short-term Debt, Weighted Average Interest Rate	0.44%	0.52%
Weighted Average Days to Maturity	'77 days	'77 days
Maturity 90 to 180 Days [Member]	'	'
Statement [Line Items]	'	'
Securities Sold under Agreements to Repurchase	401,830	621,124
Short-term Debt, Weighted Average Interest Rate	0.48%	0.54%
Weighted Average Days to Maturity	'137 days	'135 days
Maturity 180 to 270 days [Member]	'	'
Statement [Line Items]	'	'
Securities Sold under Agreements to Repurchase	305,480	147,729
Short-term Debt, Weighted Average Interest Rate	0.47%	0.49%
Weighted Average Days to Maturity	'242 days	'249 days
Maturity 271 Days to 365 Days [Member]	'	'
Statement [Line Items]	'	'
Securities Sold under Agreements to Repurchase	23,947	191,991
Short-term Debt, Weighted Average Interest Rate	0.48%	0.50%
Weighted Average Days to Maturity	'290 days	'321 days
Greater Than 12 Months [Member]	'	'
Statement [Line Items]	'	'
Securities Sold under Agreements to Repurchase	250,000	250,000
Short-term Debt, Weighted Average Interest Rate	0.59%	0.59%
Weighted Average Days to Maturity	'580 days	'853 days
US Treasury Securities [Member]	'	'
Statement [Line Items]	'	'
Securities Sold under Agreements to Repurchase	460,534	575,514
Short-term Debt, Weighted Average Interest Rate	0.02%	0.07%
Weighted Average Days to Maturity	'7 days	'2 days
Agency and Non-Agency Securities [Member]	'	'
Statement [Line Items]	'	'
Securities Sold under Agreements to Repurchase	4,461,278	6,582,678
Short-term Debt, Weighted Average Interest Rate	0.58%	0.56%
Weighted Average Days to Maturity	'87 days	'90 days
Agency Securities [Member]	'	'
Statement [Line Items]	'	'
Securities Sold under Agreements to Repurchase	$3,814,485	$5,935,610
Short-term Debt, Weighted Average Interest Rate	0.39%	0.43%
Weighted Average Days to Maturity	'99 days	'96 days

Repurchase_Agreements_Repurcha1

Repurchase Agreements Repurchase Agreements Narrative (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
Number of Repo Counterparties	33	31
Secured Debt, Repurchase Agreements	$4,921,812,000	$7,158,192,000
Maximum [Member]	'	'
Risk Of Repurchase Agreement To Stockholders Equity	5.00%	'
Top 5 Repo Counterparties [Member]	'	'
Risk Of Repurchase Agreement To Stockholders Equity	18.00%	'
Agency Securities [Member]	'	'
Agency Securities Pledged As Collateral	4,057,574,000	5,618,735,000
Repurchase Agreements [Member] | Agency Securities [Member]	'	'
Agency Securities Pledged As Collateral	4,056,943,000	5,618,735,000
Repurchase Agreements [Member] | Non-Agency Securities [Member]	'	'
Agency Securities Pledged As Collateral	845,861,000	899,176,000
Agency Securities [Member]	'	'
Collateralized Agreements	14,900,000	'
Non-Agency Securities [Member]	'	'
Collateralized Agreements	$10,500,000	'

Derivatives_Fair_Value_of_Outs

Derivatives Fair Value of Outstanding Derivatives (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Derivatives, Fair Value [Line Items]	'	'
Derivative assets, at fair value	$32,948	$108,221
Derivative Liabilities	48,742	11,327
Interest Rate Swap Assets [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative assets, at fair value	20,480	51,957
Derivative Liabilities	42,950	9,490
Payer Swaption [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative assets, at fair value	7,603	50,009
Treasury Futures Asset [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative assets, at fair value	1,196	3,399
Purchases Of TBAs And Forward Settling Agency Securities [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative assets, at fair value	3,662	2,856
Derivative Liabilities	5,730	1,837
Call Option [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative assets, at fair value	7	0
Derivative Liabilities	$62	$0

Derivatives_Effect_of_Derivati

Derivatives Effect of Derivatives on Net Income (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'	'
Realized gain (loss) on periodic interest settlements of interest rate swaps, net	($5,226)	($14,449)	($15,400)	($32,228)
Other realized gain loss on derivative instruments and other securities, net	13,704	65,258	3,236	86,675
Unrealized Gain Loss On Derivative Instrument And Trading Securities	-3,303	-105,138	-71,608	92,918
Interest Rate Swap [Member]	'	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'	'
Realized gain (loss) on periodic interest settlements of interest rate swaps, net	-5,226	-14,449	-15,400	-32,228
Other realized gain loss on derivative instruments and other securities, net	0	53,365	68	53,365
Unrealized Gain Loss On Derivative Instrument And Trading Securities	13,445	-53,588	-64,757	123,930
Interest Rate Swaption [Member]	'	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'	'
Realized gain (loss) on periodic interest settlements of interest rate swaps, net	0	0	0	0
Other realized gain loss on derivative instruments and other securities, net	-719	18,625	-17,551	15,193
Unrealized Gain Loss On Derivative Instrument And Trading Securities	-514	-32,498	-8,882	11,398
Forward Contracts [Member]	'	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'	'
Realized gain (loss) on periodic interest settlements of interest rate swaps, net	0	0	0	0
Other realized gain loss on derivative instruments and other securities, net	16,840	-42,505	22,832	-23,119
Unrealized Gain Loss On Derivative Instrument And Trading Securities	-15,004	3,433	-3,086	-50,095
US Treasury Securities [Member]	'	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'	'
Realized gain (loss) on periodic interest settlements of interest rate swaps, net	0	0	0	0
Other realized gain loss on derivative instruments and other securities, net	-222	-12,716	2,536	-13,786
Unrealized Gain Loss On Derivative Instrument And Trading Securities	-145	18,140	12,293	7,489
Treasury Futures Short [Member]	'	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'	'
Realized gain (loss) on periodic interest settlements of interest rate swaps, net	0	0	0	0
Other realized gain loss on derivative instruments and other securities, net	-653	6,650	-4,630	9,353
Unrealized Gain Loss On Derivative Instrument And Trading Securities	559	-9,930	-2,202	-2,743
Short Sales Of U S Government Securities [Member]	'	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'	'
Realized gain (loss) on periodic interest settlements of interest rate swaps, net	0	0	0	0
Other realized gain loss on derivative instruments and other securities, net	-2,964	41,839	-8,928	45,669
Unrealized Gain Loss On Derivative Instrument And Trading Securities	-377	-30,695	-5,444	2,939
Equity Securities [Member]	'	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'	'
Realized gain (loss) on periodic interest settlements of interest rate swaps, net	0	0	'	0
Other realized gain loss on derivative instruments and other securities, net	1,188	0	8,675	0
Unrealized Gain Loss On Derivative Instrument And Trading Securities	-1,375	0	502	0
Call Option [Member]	'	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'	'
Realized gain (loss) on periodic interest settlements of interest rate swaps, net	0	0	0	'
Other realized gain loss on derivative instruments and other securities, net	234	0	234	0
Unrealized Gain Loss On Derivative Instrument And Trading Securities	$108	$0	($32)	$0

Derivatives_Change_in_Derivati

Derivatives Change in Derivative Notional Amounts (Details) (USD $)

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Sep. 30, 2014

Dec. 31, 2012

Sep. 30, 2014

Sep. 30, 2014

Dec. 31, 2012

Sep. 30, 2014

Sep. 30, 2014

Dec. 31, 2012

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Dec. 31, 2012

Sep. 30, 2014

Sep. 30, 2014

In Thousands, unless otherwise specified

Interest Rate Swap [Member]

Interest Rate Swap [Member]

Interest Rate Swap [Member]

Interest Rate Swaption [Member]

Interest Rate Swaption [Member]

Interest Rate Swaption [Member]

Forward Contracts [Member]

Forward Contracts [Member]

Forward Contracts [Member]

US Treasury Securities [Member]

US Treasury Securities [Member]

Treasury Futures Short [Member]

Treasury Futures Short [Member]

Short Sales Of U S Government Securities [Member]

Short Sales Of U S Government Securities [Member]

Short Sales Of U S Government Securities [Member]

Call Option [Member]

Call Option [Member]

Derivative [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Notional Amount of Derivatives

$1,900,000

$1,200,000

$3,240,000

$3,965,000

$2,940,000

$2,100,000

$475,000

$1,150,000

($773,816)

$916,372

($522,188)

$656,000

$472,000

($150,000)

($150,000)

($23,000)

($734,500)

($425,000)

$0

($100,000)

Notional Amount Of Derivatives Not Designated As Hedging Instruments Additions During The Period

'

'

875,000

'

'

275,000

'

'

15,525,174

'

'

832,570

'

450,000

'

1,085,500

'

'

100,000

'

Notional Amount Of Derivatives Not Designated As Hedging Instruments Settlement Expiration During The Period

'

'

($150,000)

'

'

($1,900,000)

'

'

($13,834,986)

'

'

($1,016,570)

'

($450,000)

'

($1,797,000)

'

'

($200,000)

'

Derivatives_Interest_Rate_Swap

Derivatives Interest Rate Swap Agreements (Details) (USD $)	9 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Derivative [Line Items]	'	'
Notional Amount of Derivatives	$1,900,000	$1,200,000
Weighted Average Days to Maturity	'80 days	'83 days
Interest Rate Swap [Member]	'	'
Derivative [Line Items]	'	'
Interest Rate Derivatives, at Fair Value, Net	-22,470	42,467
Notional Amount of Derivatives	3,965,000	3,240,000
Weighted Average Days to Maturity	'1 year 2 months	'1 year 11 months
Interest Rate Derivative Instruments Not Designated as Hedging Instruments at Fair Value, Net	-22,470	42,467
Interest Rate Derivative Not Designated As Hedging Instruments Average Fixed Pay Rate	2.09%	1.90%
Interest Rate Derivative Not Designated As Hedging Instruments Average receive Rate	0.23%	0.24%
Derivative, Average Remaining Maturity	'5 years 0 months	'5 years 5 months
Assets [Member] | Interest Rate Swap [Member]	'	'
Derivative [Line Items]	'	'
Interest Rate Derivatives, at Fair Value, Net	20,480	51,957
Notional Amount of Derivatives	1,350,000	2,275,000
Liability [Member] | Interest Rate Swap [Member]	'	'
Derivative [Line Items]	'	'
Interest Rate Derivatives, at Fair Value, Net	-42,950	-9,490
Notional Amount of Derivatives	2,615,000	965,000
Greater Than One Year and Less Than or Equal to Three Years [Member] | Interest Rate Swap [Member]	'	'
Derivative [Line Items]	'	'
Notional Amount of Derivatives	840,000	650,000
Interest Rate Derivative Instruments Not Designated as Hedging Instruments at Fair Value, Net	-5,339	-6,612
Interest Rate Derivative Not Designated As Hedging Instruments Average Fixed Pay Rate	1.04%	0.87%
Interest Rate Derivative Not Designated As Hedging Instruments Average receive Rate	0.23%	0.24%
Derivative, Average Remaining Maturity	'1 year 6 months	'1 year 5 months
Greater Than Three Years and Less Than or Equal to Five Years [Member] | Interest Rate Swap [Member]	'	'
Derivative [Line Items]	'	'
Notional Amount of Derivatives	1,075,000	815,000
Interest Rate Derivative Instruments Not Designated as Hedging Instruments at Fair Value, Net	7,454	4,722
Interest Rate Derivative Not Designated As Hedging Instruments Average Fixed Pay Rate	1.58%	1.11%
Interest Rate Derivative Not Designated As Hedging Instruments Average receive Rate	0.23%	0.24%
Derivative, Average Remaining Maturity	'4 years 0 months	'3 years 11 months
Greater Than Five Years and Less than or Equal to Seven Years [Member] | Interest Rate Swap [Member]	'	'
Derivative [Line Items]	'	'
Notional Amount of Derivatives	1,050,000	1,025,000
Interest Rate Derivative Instruments Not Designated as Hedging Instruments at Fair Value, Net	-3,235	21,434
Interest Rate Derivative Not Designated As Hedging Instruments Average Fixed Pay Rate	2.44%	2.28%
Interest Rate Derivative Not Designated As Hedging Instruments Average receive Rate	0.23%	0.24%
Derivative, Average Remaining Maturity	'5 years 9 months	'6 years 5 months
Greater Than Seven Years and Less than or Equal to Ten Years [Member] | Interest Rate Swap [Member]	'	'
Derivative [Line Items]	'	'
Notional Amount of Derivatives	1,000,000	750,000
Interest Rate Derivative Instruments Not Designated as Hedging Instruments at Fair Value, Net	-21,350	22,923
Interest Rate Derivative Not Designated As Hedging Instruments Average Fixed Pay Rate	3.16%	3.12%
Interest Rate Derivative Not Designated As Hedging Instruments Average receive Rate	0.23%	0.24%
Derivative, Average Remaining Maturity	'8 years 2 months	'9 years 1 month
Maximum [Member]	'	'
Derivative [Line Items]	'	'
Percent of Equity at Risk Under Derivative Assets	1.00%	'
Exchange Cleared [Member] | Assets [Member] | Interest Rate Swap [Member]	'	'
Derivative [Line Items]	'	'
Interest Rate Derivatives, at Fair Value, Net	800	'
Notional Amount of Derivatives	375,000	'
Exchange Cleared [Member] | Liability [Member] | Interest Rate Swap [Member]	'	'
Derivative [Line Items]	'	'
Interest Rate Derivatives, at Fair Value, Net	-37,300	'
Notional Amount of Derivatives	$1,700,000	'

Derivatives_Interest_Rate_Swap1

Derivatives Interest Rate Swap by Remaining Maturity (Details) (USD $)	9 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Derivative [Line Items]	'	'
Notional Amount of Derivatives	$1,900,000	$1,200,000
Interest Rate Swap [Member]	'	'
Derivative [Line Items]	'	'
Derivative, Variable Interest Rate	0.23%	0.24%
Notional Amount of Derivatives	3,965,000	3,240,000
Derivative, Forward Interest Rate	1.25%	1.18%
Interest Rate Derivative Instruments Not Designated as Hedging Instruments at Fair Value, Net	-22,470	42,467
Derivative, Average Fixed Interest Rate	2.09%	1.90%
Derivative, Average Remaining Maturity	'5 years 0 months	'5 years 5 months
Interest Rate Swap [Member] | Greater Than One Year and Less Than or Equal to Three Years [Member]	'	'
Derivative [Line Items]	'	'
Derivative, Variable Interest Rate	0.23%	0.24%
Notional Amount of Derivatives	840,000	650,000
Interest Rate Derivative Instruments Not Designated as Hedging Instruments at Fair Value, Net	-5,339	-6,612
Derivative, Average Fixed Interest Rate	1.04%	0.87%
Derivative, Average Remaining Maturity	'1 year 6 months	'1 year 5 months
Interest Rate Swap [Member] | Greater Than Three Years and Less Than or Equal to Five Years [Member]	'	'
Derivative [Line Items]	'	'
Derivative, Variable Interest Rate	0.23%	0.24%
Notional Amount of Derivatives	1,075,000	815,000
Interest Rate Derivative Instruments Not Designated as Hedging Instruments at Fair Value, Net	7,454	4,722
Derivative, Average Fixed Interest Rate	1.58%	1.11%
Derivative, Average Remaining Maturity	'4 years 0 months	'3 years 11 months
Interest Rate Swap [Member] | Greater Than Five Years and Less than or Equal to Seven Years [Member]	'	'
Derivative [Line Items]	'	'
Derivative, Variable Interest Rate	0.23%	0.24%
Notional Amount of Derivatives	1,050,000	1,025,000
Interest Rate Derivative Instruments Not Designated as Hedging Instruments at Fair Value, Net	-3,235	21,434
Derivative, Average Fixed Interest Rate	2.44%	2.28%
Derivative, Average Remaining Maturity	'5 years 9 months	'6 years 5 months
Interest Rate Swap [Member] | Greater Than Seven Years and Less than or Equal to Ten Years [Member]	'	'
Derivative [Line Items]	'	'
Derivative, Variable Interest Rate	0.23%	0.24%
Notional Amount of Derivatives	1,000,000	750,000
Interest Rate Derivative Instruments Not Designated as Hedging Instruments at Fair Value, Net	($21,350)	$22,923
Derivative, Average Fixed Interest Rate	3.16%	3.12%
Derivative, Average Remaining Maturity	'8 years 2 months	'9 years 1 month

Derivatives_Interest_Rate_Swap2

Derivatives Interest Rate Swaptions (Details) (USD $)

12 Months Ended

12 Months Ended

9 Months Ended

9 Months Ended

9 Months Ended

9 Months Ended

9 Months Ended

In Thousands, unless otherwise specified

Dec. 31, 2013

Sep. 30, 2014

Sep. 30, 2014

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Interest Rate Swaption [Member]

Interest Rate Swaption [Member]

Interest Rate Swaption [Member]

3 Months or Less [Member]

Greater Than 3 Months and Less Than 12 Months [Domain]

Greaterthan12Monthsandlessthanorequalto24Months [Member]

Greater than 24 Months [Member]

Interest Rate Swaption [Member]

Interest Rate Swaption [Member]

Interest Rate Swaption [Member]

Interest Rate Swaption [Member]

Interest Rate Swaption [Member]

Interest Rate Swaption [Member]

Interest Rate Swaption [Member]

Interest Rate Swaption [Member]

Interest Rate Swaption [Member]

Interest Rate Swaption [Member]

3 Months or Less [Member]

3 Months or Less [Member]

Greater Than 3 Months and Less Than 12 Months [Domain]

Greater Than 3 Months and Less Than 12 Months [Domain]

Greaterthan12Monthsandlessthanorequalto24Months [Member]

Greaterthan12Monthsandlessthanorequalto24Months [Member]

Greater than 24 Months [Member]

Greater than 24 Months [Member]

Derivative [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Options At Cost

$43,722

'

'

'

'

$17,015

$13,868

$8,105

$4,734

$10,198

'

$179

'

$4,765

'

$1,308

'

$3,946

'

Interest Rate Derivatives, at Fair Value, Net

'

'

'

'

'

'

'

'

'

7,603

50,009

88

19,841

2,835

10,406

635

8,979

4,045

10,783

Weighted Average Years to Swaption Maturity

'0 years 10 months 24 days

'

'

'

'

'0 years 1 month 6 days

'0 years 7 months 6 days

'1 year 8 months 12 days

'3 years 2 months 12 days

'1 year 9 months

'

'0 years 0 months 6 days

'

'0 years 8 months

'

'1 year 6 months

'

'2 years 8 months

'

Notional Amount of Interest Rate Derivatives

$1,200,000

$1,900,000

$475,000

$2,100,000

$1,150,000

'

'

'

'

$475,000

$2,100,000

$50,000

$925,000

$100,000

$550,000

$100,000

$400,000

$225,000

$225,000

Interest Rate Derivative Not Designated As Hedging instruments Pay Rate

2.99%

'

'

'

'

2.59%

2.94%

3.63%

3.62%

3.11%

'

1.30%

'

3.34%

'

4.13%

'

2.97%

'

Derivatives Average Term

'7 years 6 months

'

'

'

'

'8 years 0 months

'8 years 2 months

'6 years 4 months

'5 years 11 months

'5 years 0 months

'

'3 years 0 months

'

'7 years 0 months

'

'7 years 0 months

'

'3 years 8 months

'

Derivatives_TBA_Securities_Det

Derivatives TBA Securities (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Derivative [Line Items]	'	'
Notional Amount of Derivatives	$1,900,000	$1,200,000
TBA securities Fifteen Year and Thirty Year Securities [Member]	'	'
Derivative [Line Items]	'	'
Notional Amount of Derivatives	916,372	-773,816
Derivative, Fair Value, Net	-2,068	1,019
Derivative Assets [Member] | TBA securities Fifteen Year and Thirty Year Securities [Member]	'	'
Derivative [Line Items]	'	'
Notional Amount of Derivatives	905,392	-252,896
Derivative, Fair Value, Net	3,662	2,856
Derivative Assets [Member] | TBA securities Fifteen Year and Thirty Year Securities [Member] | Long [Member]	'	'
Derivative [Line Items]	'	'
Notional Amount of Derivatives	1,005,970	210,600
Derivative, Fair Value, Net	3,449	158
Derivative Assets [Member] | TBA securities Fifteen Year and Thirty Year Securities [Member] | Short [Member]	'	'
Derivative [Line Items]	'	'
Notional Amount of Derivatives	-100,578	-463,496
Derivative, Fair Value, Net	213	2,698
Derivative liabilities [Member] | TBA securities Fifteen Year and Thirty Year Securities [Member]	'	'
Derivative [Line Items]	'	'
Notional Amount of Derivatives	10,980	-520,920
Derivative, Fair Value, Net	-5,730	-1,837
Derivative liabilities [Member] | TBA securities Fifteen Year and Thirty Year Securities [Member] | Long [Member]	'	'
Derivative [Line Items]	'	'
Notional Amount of Derivatives	433,080	0
Derivative, Fair Value, Net	-3,808	0
Derivative liabilities [Member] | TBA securities Fifteen Year and Thirty Year Securities [Member] | Short [Member]	'	'
Derivative [Line Items]	'	'
Notional Amount of Derivatives	-422,100	-520,920
Derivative, Fair Value, Net	($1,922)	($1,837)

Derivatives_US_Treasury_Securi

Derivatives U.S. Treasury Securities and Futures (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Open Option Contracts Written [Line Items]	'	'
US Government Securities, at Carrying Value (including pledged securities of $460,333 and $571,145, respectively)	$467,201	$637,342
Notional Amount of Derivatives	1,900,000	1,200,000
Receivables from Brokers-Dealers and Clearing Organizations	49,131	608,646
Derivative Liabilities	48,742	11,327
Obligation to Return Securities Borrowed Under Reverse Repurchase Agreements at Fair Value	742,642	22,530
Receivable Under Reverse Repurchase Agreements	745,443	22,736
US Treasury Securities [Member]	'	'
Open Option Contracts Written [Line Items]	'	'
Notional Amount of Derivatives	472,000	656,000
Treasury Futures Short [Member]	'	'
Open Option Contracts Written [Line Items]	'	'
Notional Amount of Derivatives	-150,000	-150,000
Derivative Liabilities	$1,200	$3,400

Derivatives_REIT_Equity_Securi

Derivatives REIT Equity Securities (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]	'	'	'	'	'
Marketable Securities, Equity Securities	$0	'	$0	'	$38,807,000
Unrealized Gain Loss On Derivative Instrument And Trading Securities	-3,303,000	-105,138,000	-71,608,000	92,918,000	'
Marketable Securities, Realized Gain (Loss)	'	'	6,800,000	'	'
Other realized gain loss on derivative instruments and other securities, net	13,704,000	65,258,000	3,236,000	86,675,000	'
Investment Income, Dividend	'	'	1,800,000	'	'
Equity Securities [Member]	'	'	'	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'	'	'	'
Investment Owned, at Cost	'	'	'	'	39,300,000
Equity Securities [Member]	'	'	'	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'	'	'	'
Unrealized Gain Loss On Derivative Instrument And Trading Securities	-1,375,000	0	502,000	0	'
Other realized gain loss on derivative instruments and other securities, net	$1,188,000	$0	$8,675,000	$0	'

Derivatives_Credit_Risk_Contin

Derivatives Credit Risk Contingent Features (Details) (Maximum [Member])	Sep. 30, 2014
Maximum [Member]	'
Derivative [Line Items]	'
Percent of Equity at Risk Under Derivative Assets	1.00%

Offsetting_Assets_and_Liabilit2

Offsetting Assets and Liabilities Offsetting of Financial Assets and Liabilities (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities Sold under Agreements to Repurchase	'	$7,158,192
Derivative Assets [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Gross Amount of Recognized Assets (Liabilities)	28,083	101,966
Gross Amounts Offset on the Balance Sheet	0	0
Net Amount of Assets (Liabilities) Presented on the Balance Sheet	-28,083	-101,966
Gross Amounts of Financial Instruments Not Offset on the Balance Sheet	-6,288	-9,490
Gross Amounts of Cash Collateral Not Offset on the Balance Sheet	-8,205	-45,084
Net Amount After Deducting Gross Amounts Not Offset on the Balance Sheet From Net Amount of Assets (Liabilities) Presented on the Balance Sheet	13,590	47,392
Derivative Assets [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Gross Amount of Recognized Assets (Liabilities)	4,964,762	7,167,682
Gross Amounts Offset on the Balance Sheet	0	0
Net Amount of Assets (Liabilities) Presented on the Balance Sheet	-4,964,762	-7,167,682
Gross Amounts of Financial Instruments Not Offset on the Balance Sheet	-573,175	-32,226
Gross Amounts of Cash Collateral Not Offset on the Balance Sheet	-4,391,587	-7,135,456
Net Amount After Deducting Gross Amounts Not Offset on the Balance Sheet From Net Amount of Assets (Liabilities) Presented on the Balance Sheet	0	0
Securities Sold under Agreements to Repurchase [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Gross Amount of Recognized Assets (Liabilities)	745,443	22,736
Gross Amounts Offset on the Balance Sheet	0	0
Net Amount of Assets (Liabilities) Presented on the Balance Sheet	-745,443	-22,736
Gross Amounts of Financial Instruments Not Offset on the Balance Sheet	-566,887	-22,736
Gross Amounts of Cash Collateral Not Offset on the Balance Sheet	-176,990	0
Net Amount After Deducting Gross Amounts Not Offset on the Balance Sheet From Net Amount of Assets (Liabilities) Presented on the Balance Sheet	1,566	0
Assets [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Gross Amount of Recognized Assets (Liabilities)	773,526	124,702
Gross Amounts Offset on the Balance Sheet	0	0
Net Amount of Assets (Liabilities) Presented on the Balance Sheet	-773,526	-124,702
Gross Amounts of Financial Instruments Not Offset on the Balance Sheet	-573,175	-32,226
Gross Amounts of Cash Collateral Not Offset on the Balance Sheet	-185,195	-45,084
Net Amount After Deducting Gross Amounts Not Offset on the Balance Sheet From Net Amount of Assets (Liabilities) Presented on the Balance Sheet	15,156	47,392
Derivative liabilities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Gross Amount of Recognized Assets (Liabilities)	42,950	9,490
Gross Amounts Offset on the Balance Sheet	0	0
Net Amount of Assets (Liabilities) Presented on the Balance Sheet	-42,950	-9,490
Gross Amounts of Financial Instruments Not Offset on the Balance Sheet	-6,288	-9,490
Gross Amounts of Cash Collateral Not Offset on the Balance Sheet	-36,662	0
Net Amount After Deducting Gross Amounts Not Offset on the Balance Sheet From Net Amount of Assets (Liabilities) Presented on the Balance Sheet	0	0
Repurchase Agreements [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Gross Amount of Recognized Assets (Liabilities)	'	7,158,192
Gross Amounts Offset on the Balance Sheet	0	0
Net Amount of Assets (Liabilities) Presented on the Balance Sheet	4,921,812	-7,158,192
Gross Amounts of Financial Instruments Not Offset on the Balance Sheet	-566,887	-22,736
Gross Amounts of Cash Collateral Not Offset on the Balance Sheet	-4,354,925	-7,135,456
Net Amount After Deducting Gross Amounts Not Offset on the Balance Sheet From Net Amount of Assets (Liabilities) Presented on the Balance Sheet	0	0
Securities Sold under Agreements to Repurchase	$4,921,812	'

Fair_Value_Measurements_Financ

Fair Value Measurements Financial Instruments Measured on a Recurring Basis (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value	$4,259,763	$5,641,682
US Government Securities, at Carrying Value (including pledged securities of $460,333 and $571,145, respectively)	-467,201	-637,342
Derivative Asset	32,948	108,221
Servicing Asset at Fair Value, Amount	100,300	'
Derivative liabilities, at fair value	48,742	11,327
Obligation to Return Securities Borrowed Under Reverse Repurchase Agreements at Fair Value	742,642	22,530
Servicing Liability	14,470	15,608
Fair Value, Measurements, Recurring [Member]	'	'
Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value	4,259,763	5,641,682
Non-Agency Security, at Fair Value	1,075,867	1,011,217
Marketable Securities	'	38,807
US Government Securities, at Carrying Value (including pledged securities of $460,333 and $571,145, respectively)	-467,201	-637,342
Derivative Asset	32,948	108,221
Servicing Asset at Fair Value, Amount	100,314	15,608
Assets, Fair Value Disclosure, Recurring	5,936,093	7,452,877
Derivative liabilities, at fair value	48,742	11,327
Obligation to Return Securities Borrowed Under Reverse Repurchase Agreements at Fair Value	742,642	22,530
Servicing Liability	14,470	15,608
Liabilities, Fair Value Disclosure, Recurring	805,854	49,465
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]	'	'
Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value	0	0
Non-Agency Security, at Fair Value	0	0
Marketable Securities	'	38,807
US Government Securities, at Carrying Value (including pledged securities of $460,333 and $571,145, respectively)	-467,201	-637,342
Derivative Asset	0	0
Servicing Asset at Fair Value, Amount	0	0
Assets, Fair Value Disclosure, Recurring	467,201	676,149
Derivative liabilities, at fair value	0	0
Obligation to Return Securities Borrowed Under Reverse Repurchase Agreements at Fair Value	742,642	22,530
Servicing Liability	0	0
Liabilities, Fair Value Disclosure, Recurring	742,642	22,530
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]	'	'
Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value	4,259,763	5,641,682
Non-Agency Security, at Fair Value	1,075,867	1,011,217
Marketable Securities	'	0
US Government Securities, at Carrying Value (including pledged securities of $460,333 and $571,145, respectively)	0	0
Derivative Asset	32,948	108,221
Servicing Asset at Fair Value, Amount	0	0
Assets, Fair Value Disclosure, Recurring	5,368,578	6,761,120
Derivative liabilities, at fair value	48,742	11,327
Obligation to Return Securities Borrowed Under Reverse Repurchase Agreements at Fair Value	0	0
Servicing Liability	0	0
Liabilities, Fair Value Disclosure, Recurring	48,742	11,327
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]	'	'
Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value	0	0
Non-Agency Security, at Fair Value	0	'
Marketable Securities	'	0
US Government Securities, at Carrying Value (including pledged securities of $460,333 and $571,145, respectively)	0	0
Derivative Asset	0	0
Servicing Asset at Fair Value, Amount	100,314	15,608
Assets, Fair Value Disclosure, Recurring	100,314	15,608
Derivative liabilities, at fair value	0	0
Obligation to Return Securities Borrowed Under Reverse Repurchase Agreements at Fair Value	0	0
Servicing Liability	14,470	15,608
Liabilities, Fair Value Disclosure, Recurring	$14,470	$15,608

Fair_Value_Measurements_Level_

Fair Value Measurements Level 3 Financial Assets and Liabilities (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'	'	'	'	'
Unrealized gain (loss) mortgage servicing rights	($3,076)	$0	($3,705)	$0	'
Other Operating Income (Expense), Net	-3,132	0	-10,827	0	'
Amortization of Mortgage Servicing Rights (MSRs)	-1,728	'	-2,830	0	'
Interest Receivable	14,523	'	14,523	'	20,620
Unrealized Gain (Loss) on Investments	-21,103	-424	-11,255	6,303	'
Purchased MSR [Member]	'	'	'	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'	'	'	'	'
Unrealized gain (loss) mortgage servicing rights	'	'	-3,705	'	'
Amortization of Mortgage Servicing Rights (MSRs)	'	'	2,830	'	'
Fair Value, Inputs, Level 3 [Member] | Servicing Contracts [Member]	'	'	'	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'	'	'	'	'
Unrealized gain (loss) mortgage servicing rights	'	'	-3,875	'	'
Other Operating Income (Expense), Net	'	'	-7,673	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	100,314	'	100,314	'	15,608
Amortization of Mortgage Servicing Rights (MSRs)	'	'	-3,798	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	'	'	92,379	'	'
Fair Value, Inputs, Level 3 [Member] | Servicing Contracts [Member] | MSR Treated as Financing Arrangement [Member]	'	'	'	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'	'	'	'	'
Unrealized gain (loss) mortgage servicing rights	'	'	-170	'	'
Other Operating Income (Expense), Net	'	'	-1,138	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	14,470	'	14,470	'	15,608
Amortization of Mortgage Servicing Rights (MSRs)	'	'	-968	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	'	'	0	'	'
Fair Value, Inputs, Level 3 [Member] | Servicing Contracts [Member] | Purchased MSR [Member]	'	'	'	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'	'	'	'	'
Unrealized gain (loss) mortgage servicing rights	'	'	-3,705	'	'
Other Operating Income (Expense), Net	'	'	-6,535	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	85,844	'	85,844	'	0
Amortization of Mortgage Servicing Rights (MSRs)	'	'	-2,830	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	'	'	92,379	'	'
Fair Value, Inputs, Level 3 [Member] | Non-Agency Securities [Member]	'	'	'	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'	'	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	'	'	'	'	$0

Fair_Value_Measurements_Level_1

Fair Value Measurements Level 3 Unobservable Inputs (Details) (USD $)

3 Months Ended

9 Months Ended

9 Months Ended

9 Months Ended

9 Months Ended

9 Months Ended

In Thousands, unless otherwise specified

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

MSR Treated as Financing Arrangement [Member]

MSR Treated as Financing Arrangement [Member]

MSR Treated as Financing Arrangement [Member]

MSR Treated as Financing Arrangement [Member]

Purchased MSR [Member]

Purchased MSR [Member]

Purchased MSR [Member]

Purchased MSR [Member]

Purchased MSR [Member]

Servicing Contracts [Member]

Servicing Contracts [Member]

Servicing Contracts [Member]

Servicing Contracts [Member]

Servicing Contracts [Member]

Servicing Contracts [Member]

Fair Value, Inputs, Level 3 [Member]

Fair Value, Inputs, Level 3 [Member]

Maximum [Member]

Minimum [Member]

Weighted Average [Member]

Maximum [Member]

Minimum [Member]

Weighted Average [Member]

Fair Value, Inputs, Level 3 [Member]

Fair Value, Inputs, Level 3 [Member]

MSR Treated as Financing Arrangement [Member]

MSR Treated as Financing Arrangement [Member]

Purchased MSR [Member]

Purchased MSR [Member]

Fair Value, Inputs, Level 3 [Member]

Fair Value, Inputs, Level 3 [Member]

Fair Value, Inputs, Level 3 [Member]

Fair Value, Inputs, Level 3 [Member]

Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Servicing Asset at Fair Value, Amount

$100,300

$100,300

'

$100,314

$15,608

$100,314

$15,608

$14,470

'

'

'

$85,844

$0

'

'

'

'

'

'

'

'

'

Constant Prepayment Speed

'

'

'

'

'

'

'

'

34.50%

9.70%

14.70%

'

'

8.10%

7.30%

7.70%

'

'

'

'

'

'

Loss Severity

'

'

'

'

'

'

'

'

28.20%

0.00%

7.40%

'

'

0.40%

0.20%

0.30%

'

'

'

'

'

'

Discount Rate

'

'

'

'

'

'

'

'

16.00%

16.00%

16.00%

'

'

9.30%

8.30%

8.70%

'

'

'

'

'

'

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

100,314

15,608

14,470

15,608

85,844

0

Amortization of Mortgage Servicing Rights (MSRs)

($1,728)

($2,830)

$0

'

'

'

'

'

'

'

'

$2,830

'

'

'

'

($3,798)

'

($968)

'

($2,830)

'

Mortgage_Servicing_Rights_Deta

Mortgage Servicing Rights (Details) (USD $)	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Mortgage Servicing Rights, Number of Loans	34,608	'
Mortgage Servicing Rights, Unpaid Principal	$7,300,000,000	'
Servicing Asset at Fair Value, Amount	100,300,000	'
Servicing Asset at Fair Value, Additions	-87,820,000	0
MSR Treated as Financing Arrangement [Member]	'	'
Servicing Asset at Fair Value, Amount	$14,470,000	'

Mortgage_Servicing_Rights_Roll

Mortgage Servicing Rights Rollforward of Mortgage Servicing Rights (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Dec. 31, 2013
					Purchased MSR [Member]	Purchased MSR [Member]
Servicing Assets at Fair Value [Line Items]	'	'	'	'	'	'
Servicing Asset at Fair Value, Amount	$100,300	'	$100,300	'	$85,844	$0
Servicing Asset at Fair Value, Additions	'	'	-87,820	0	93,414	'
Unrealized gain (loss) mortgage servicing rights	-3,076	0	-3,705	0	-3,705	'
Amortization of Mortgage Servicing Rights (MSRs)	1,728	'	2,830	0	-2,830	'
Other changes in fair value of mortgage servicing rights	'	'	'	'	($1,035)	'

Mortgage_Servicing_Rights_Comp

Mortgage Servicing Rights Components of Servicing Revenue and Expense (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Components of Servicing Revenue [Line Items]	'	'	'	'
Contractually Specified Servicing Fees, Amount	$9,247	'	$22,572	'
Ancillary Fee Income Generated by Servicing Financial Assets, Amount	3,834	'	11,462	'
Amortization of Mortgage Servicing Rights (MSRs)	-1,728	'	-2,830	0
Other Nonoperating Income (Expense)	13,081	'	34,034	'
Labor and Related Expense	8,678	'	25,353	'
Occupancy, Net	3,831	'	10,111	'
Other Expenses	1,976	'	6,567	'
Other Noninterest Expense	16,213	0	44,861	0
Other Operating Income (Expense), Net	($3,132)	$0	($10,827)	$0

Other_Assets_Schedule_of_Other

Other Assets Schedule of Other Assets (Details) (USD $)	9 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Schedule of Other Assets [Line Items]	'	'
Reductions in Other Assets, Amount	$2,000,000	'
Property, Plant and Equipment, Gross	4,784,000	4,024,000
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	-1,474,000	-164,000
Property, Plant and Equipment, Net	3,310,000	3,860,000
Servicing advances	16,138,000	33,358,000
Servicing Asset at Fair Value, Amount	100,300,000	'
Prepaid Expense, Current	5,468,000	6,978,000
Goodwill	15,000,000	17,000,000
Other Assets, Miscellaneous, Current	5,722,000	4,387,000
Other Assets	$45,638,000	$65,583,000

Other_Assets_Intangible_Assets

Other Assets Intangible Assets (Details) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014
Intangible Assets [Abstract]	'
Reductions in Other Assets, Amount	$2

Other_Liabilities_Schedule_of_

Other Liabilities Schedule of Other Liabilities (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Derivative, Collateral, Obligation to Return Cash	$4,468	$32,463
Due to Affiliate, Current	1,849	1,885
Other Payables to Broker-Dealers and Clearing Organizations	520	0
Payable for Equity Securities Purchased	0	4,581
Other Accrued Liabilities, Current	4,559	0
Interest Payable, Current	7,859	4,401
Servicing Liability	14,470	15,608
Sales and Excise Tax Payable, Current	350	574
Other Accounts Payable and Accrued Liabilities	11,349	10,203
Accounts Payable and Accrued Liabilities	$45,424	$69,715

Stockholders_Equity_Details

Stockholder's Equity (Details) (USD $)	9 Months Ended
In Millions, except Per Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Jun. 30, 2013	Dec. 31, 2012
Stockholders' Equity Attributable to Parent [Abstract]	'	'	'	'
Stock Repurchase Program, Authorized Amount	'	$150	$100	$50
Stock Repurchased During Period, Shares	0.2	'	'	'
Treasury Stock Acquired, Average Cost Per Share	$19.67	'	'	'
Stock Repurchased During Period, Value	4.2	'	'	'
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$134.90	'	'	'

Stockholders_Equity_Preferred_

Stockholder's Equity Preferred Stock Offering (Details) (USD $)	9 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Class of Stock [Line Items]	'	'	'
Preferred Stock, Shares Authorized	50,000,000	'	50,000,000
Preferred Stock, Shares Issued	2,200,000	'	0
Sale of Stock, Price Per Share	$24.21	'	'
Proceeds from Issuance of Preferred Stock and Preference Stock	$53,039	$0	'
Preferred Stock, Dividend Rate, Percentage	8.13%	'	'
Preferred Stock, Redemption Price Per Share	$25	'	'
Preferred Class A [Member]	'	'	'
Class of Stock [Line Items]	'	'	'
Preferred Stock, Shares Authorized	50,000,000	'	'
Preferred Stock, Shares Issued	2,300,000	'	'
Preferred Stock, Dividend Rate, Percentage	8.13%	'	'
Preferred Stock, Shares Subscribed but Unissued	47,800,000	'	'

Stockholders_Equity_Stock_Repu

Stockholder's Equity Stock Repurchase Program (Details) (USD $)	9 Months Ended
In Millions, except Per Share data, unless otherwise specified	Sep. 30, 2014
Class of Stock [Line Items]	'
Stock Repurchased During Period, Shares	0.2
Treasury Stock Acquired, Average Cost Per Share	$19.67
Stock Repurchased During Period, Value	$4.20
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$134.90