MTGE Investment (MTGE) 10-K 28 Feb 14 2013 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information Document (USD $)	12 Months Ended
	Dec. 31, 2013	Feb. 01, 2014	Jun. 30, 2013
Document and Entity Information [Abstract]	'	'	'
Document Type	'10-K	'	'
Amendment Flag	'false	'	'
Document Period End Date	31-Dec-13	'	'
Document Fiscal Year Focus	'2013	'	'
Document Fiscal Period Focus	'FY	'	'
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	'	51,355,993	'
Trading Symbol	'MTGE	'	'
Entity Well-known Seasoned Issuer	'Yes	'	'
Entity Voluntary Filers	'No	'	'
Entity Current Reporting Status	'Yes	'	'
Entity Public Float	'	'	$808,765,689

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Assets:	'	'
Agency securities, at fair value (including pledged securities of $5,618,735 and $6,276,993, respectively)	$5,641,682	$6,367,042
Non-agency securities, at fair value (including pledged securities of $899,176 and $545,665, respectively)	1,011,217	681,403
Marketable Securities, Equity Securities	38,807	0
US Government Securities, at Carrying Value	637,342	0
Cash and cash equivalents	206,398	157,314
Restricted cash	21,005	28,493
Interest receivable	20,620	18,265
Derivative assets, at fair value	108,221	23,043
Receivable for agency securities sold	608,646	0
Receivable under reverse repurchase agreements	22,736	418,888
Other assets	81,191	1,692
Total assets	8,397,865	7,696,140
Liabilities:	'	'
Secured Debt, Repurchase Agreements	7,158,192	6,245,791
Derivative liabilities, at fair value	11,327	63,726
Dividend payable	33,381	32,368
Obligation to Return Securities Borrowed Under Reverse Repurchase Agreements, at Fair Value	22,530	421,077
Accounts payable and other accrued liabilities	69,715	7,616
Total liabilities	7,295,145	6,770,578
Stockholders' equity:	'	'
Preferred stock, $0.01 par value; 50,000 shares authorized, 0 shares issued and outstanding, respectively	0	0
Common stock, $0.01 par value; 300,000 shares authorized, 51,356 and 35,964 shares issued and outstanding, respectively	514	360
Additional paid-in capital	1,201,826	772,008
Retained earnings	-99,620	153,194
Total stockholders' equity	1,102,720	925,562
Total liabilities and stockholders' equity	$8,397,865	$7,696,140

Consolidated_Statement_Of_Oper

Consolidated Statement Of Operations (USD $)	5 Months Ended	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2012
Interest income:	'	'	'
Agency securities	$15,832	$199,964	$122,082
Non-agency securities	533	55,368	23,029
Investment Income, Interest	49	367	309
Interest expense	1,737	38,754	22,067
Net interest income	14,677	216,945	123,353
Other gains (losses):	'	'	'
Realized gain on agency securities, net	3,437	-170,252	73,610
Realized gain on non-agency securities, net	0	16,856	1,780
Realized loss on periodic settlements of interest rate swaps, net	-1,743	-41,006	-18,458
Realized gain on other derivatives and securities, net	-3,856	112,573	-46,748
Unrealized gain on agency securities, net	13,817	-315,784	123,456
Unrealized gain on non-agency securities, net	-433	19,391	64,310
Unrealized gain and net interest income on linked transactions, net	-1,050	0	3,384
Unrealized loss on other derivatives and securities, net	2,405	-107,546	58,669
Other Operating Income	0	3,350	0
Total other gains, net	7,767	-267,326	142,665
Expenses:	'	'	'
Asset Management Costs	1,188	18,680	9,638
General and administrative expenses	1,555	7,241	5,018
Other Noninterest Expense	0	7,489	0
Total expenses	2,743	33,410	14,656
Income before excise tax	19,701	-83,791	251,362
Excise tax	32	679	1,182
Net income	$19,669	($84,470)	$250,180
Net income per common sharebbasic and diluted	$1.97	($1.59)	$8.90
Weighted Average Number of Shares Outstanding, Basic and Diluted	10,006	53,015	28,100

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 Aug. 09, 2011	$1	$0	$0	$1	$0
Balance, Common Stock, shares at Aug. 09, 2011	'	'	0	'	'
Preferred Stock, Shares Outstanding at Aug. 09, 2011	'	0	'	'	'
Net income	19,669	'	'	'	'
Issuance of common stock, shares	'	'	10,000	'	'
Issuance of common stock, value	199,121	'	100	199,021	'
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures	0	'	6	'	'
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures	'	'	0	'	'
Stock-based compensation	16	'	'	16	'
Common dividends declared	10,006	'	'	'	10,006
Balance at Dec. 31, 2011	208,801	0	100	199,038	9,663
Preferred Stock, Shares Outstanding at Dec. 31, 2011	'	0	'	'	'
Balance, Common Stock, shares at Dec. 31, 2011	'	'	10,006	'	'
Net income	250,180	'	'	'	'
Issuance of common stock, shares	'	'	26,250	'	'
Issuance of common stock, value	579,931	'	263	579,668	'
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures	0	'	6	'	'
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures	'	'	0	'	'
Stock Repurchased During Period, Shares	300	'	-298	'	'
Stock Repurchased During Period, Value	6,800	'	-3	'	'
Stock Repurchased and Retired During Period, Value	-6,777	'	'	-6,774	'
Stock-based compensation	76	'	'	76	'
Common dividends declared	106,649	'	'	'	106,649
Balance at Dec. 31, 2012	925,562	0	360	772,008	153,194
Preferred Stock, Shares Outstanding at Dec. 31, 2012	'	0	'	'	'
Balance, Common Stock, shares at Dec. 31, 2012	'	'	35,964	'	'
Net income	-84,470	'	'	'	'
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	7,600	'	-7,616	'	'
Stock Repurchased During Period, Value	154,100	'	-76	'	'
Stock Repurchased and Retired During Period, Value	-154,078	'	'	-154,002	'
Stock-based compensation	135	'	'	135	'
Common dividends declared	168,344	'	'	'	168,344
Balance at Dec. 31, 2013	$1,102,720	$0	$514	$1,201,826	($99,620)
Preferred Stock, Shares Outstanding at Dec. 31, 2013	'	0	'	'	'
Balance, Common Stock, shares at Dec. 31, 2013	'	'	51,356	'	'

Consolidated_Statement_Of_Cash

Consolidated Statement Of Cash Flows (USD $)	5 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2012
CASH FLOWS USED IN OPERATING ACTIVITIES:	'	'	'
Net income (loss)	$19,669	($84,470)	$250,180
Adjustments to reconcile net income to net cash used in operating activities:	'	'	'
Investment Income, Amortization of Premium	5,012	38,915	32,898
Accretion of Discount	-799	-35,496	-14,209
Unrealized loss (gain) on securities and derivatives, net	9,121	-188,847	131,774
Realized loss (gain) on agency securities, net	3,437	-170,252	73,610
Realized gain on non-agency securities, net	0	16,856	1,780
Realized loss (gain) on derivatives and securities, net	-3,856	70,590	-65,206
Stock-based compensation	16	135	76
Increase in interest receivable	5,566	2,355	12,699
Increase in other assets	589	-1,840	1,103
Increase in accounts payable and other accrued liabilities	2,370	33,954	5,246
Net cash provided by operating activities	11,411	224,176	118,431
CASH FLOWS USED IN INVESTING ACTIVITIES:	'	'	'
Purchases of agency securities	2,562,190	8,914,575	8,937,456
Purchases of non-agency securities	28,525	561,932	600,470
Proceeds from sale of agency securities	712,191	7,817,303	4,163,571
Proceeds from sale of non-agency securities	0	197,259	32,341
Principal collections on agency securities	39,339	689,035	393,909
Proceeds From Principal Collection Of Non Agency Mortgag eBacked Securities	2,778	106,602	50,058
Payments for Securities Purchased under Agreements to Resell	50,562	-396,152	368,325
Purchase Of US Treasury Securities	614,581	8,479,099	3,305,123
Proceeds from sale of U.S. Treasury securities	661,424	7,471,222	3,667,490
Proceeds from terminations of interest rate swaptions	0	48,405	0
Payment of premiums for interest rate swaptions	884	46,362	28,103
Payments for (Proceeds from) Other Investing Activities	-52,928	-74,009	-80,261
Net cash flows used in investing activities	-1,893,938	-1,349,999	-5,012,369
CASH FLOWS FROM FINANCING ACTIVITIES:	'	'	'
Payments of Dividends	-2,001	-167,331	-82,286
Proceeds from common stock offerings, net of offering costs	199,122	583,915	579,931
Payments for Repurchase of Common Stock	0	-154,078	-6,777
Proceeds from repurchase agreements	4,563,803	103,914,609	32,504,640
Repayments of Short-term Debt	-2,857,523	-103,002,208	-28,004,342
Proceeds from (Payments for) Other Financing Activities	36,554	0	2,658
Net cash flow from financing activities	1,939,955	1,174,907	4,993,824
Net increase in cash and cash equivalents	57,428	49,084	99,886
Cash and cash equivalents at beginning of period	0	157,314	57,428
Cash and cash equivalents at end of period	57,428	206,398	157,314
Supplemental disclosure of cash flow information:	'	'	'
Interest Paid	1,105	37,892	19,581
Income Taxes Paid	0	1,277	42
Non-Agency Securities Recorded Upon de-linked of Linked Transactions	0	0	58,061
Repurchase Agreements Recorded Upon de-linking of Linked Transactions	$0	$0	($39,212)

Organization

Organization	12 Months Ended
	Dec. 31, 2013
Organization [Abstract]	'
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]	'
	Organization
	American Capital Mortgage Investment Corp. (referred to throughout this report as the "Company", "we", "us" and "our") was 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, we acquired Residential Credit Solutions, Inc. ("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 9 - Other Assets for additional information.

Summary_of_Significant_Account

Summary of Significant Accounting Policies (Notes)	12 Months Ended
	Dec. 31, 2013
Summary of Significant Accounting Policies [Abstract]	'
Summary of Significant Accounting Policies	'
	Summary of Significant Accounting Policies
	Basis of Presentation and Consolidation
	The consolidated financial statements of the Company are prepared in accordance with U.S. generally accepted accounting principles ("GAAP"). Our consolidated financial statements include the accounts of our wholly-owned taxable REIT subsidiaries, American Capital Mortgage Investment TRS, LLC and RCS. Significant intercompany accounts and transactions have been eliminated. The consolidated financial statements reflect the acquisition of the RCS, which was accounted for as a business combination.
	Use of Estimates
	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, disclosure of contingent assets and liabilities at the date of the financial statements and revenues and expenses during the period reported. Actual results could differ from those estimates.
	Earnings per Share
	Basic earnings per share ("EPS") is computed by dividing net income by the weighted average number of common shares outstanding during the period. Diluted EPS assumes the conversion, exercise or issuance of all potential common stock equivalents unless the effect is to reduce a loss or increase the income per share.
	Cash and Cash Equivalents
	Cash and cash equivalents consist of unrestricted demand deposits and highly liquid investments with original maturities of three months or less. Cash and cash equivalents are carried at cost, which approximates fair value.
	Restricted Cash and Cash Equivalents
	Restricted cash includes cash pledged as collateral for clearing and executing trades, interest rate swaps and repurchase agreements. Restricted cash is carried at cost, which approximates fair value.
	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 economic hedging instruments. See Note 8 - 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 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
	The Company’s MSR represent the right to service mortgage loans in return for a servicing fee. The Company 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. These advances are reported as servicing advances within the other assets line item on the consolidated balance sheets.
	MSR are reported at fair value within the other assets line item on the consolidated balance sheets. Changes in the fair value of MSR as well as servicing fee income are reported within servicing and other income on the consolidated statements of operations. The related servicing expenses are recorded in servicing and other operating expenses on the consolidated statements of operations. See Note 9 - Other Assets 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 for adequate compensation, 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 any MSR financing liabilities at estimated fair value, with changes in fair value reflected in income during the period in which they occur. See Note 10 - Accounts Payable and Other Accrued Liabilities for the presentations of our mortgage servicing liability.
	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 (loss) 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, other than those treated as Linked Transactions (see Derivatives below), 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
	We from time to time borrow securities to cover short sales of U.S. Treasury securities through reverse repurchase transactions under our master repurchase agreements (see Derivatives Instruments below). We account for these as securities borrowing transactions and recognize an obligation to return the borrowed securities at fair value on the balance sheet 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.
	Manager Compensation
	The management agreement provides for the payment to our Manager of a management fee and reimbursement of certain operating expenses, which are accrued and expensed during the period for which they are earned or incurred. Refer to Note 11 for disclosure on the terms of the management agreement.
	Derivatives
	We maintain 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 also may 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 both our own and our counterparties’ 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 risk is not significant to the overall valuation of these agreements.
	The payment of periodic settlements of net interest on interest rate swaps are 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 (loss) 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 (loss) 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 (loss) 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 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 (loss) 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.
	Linked Transactions
	If we finance the purchase of securities with repurchase agreements with the same counterparty from whom the securities are purchased and both transactions are entered into contemporaneously or in contemplation of each other, the transactions are presumed not to meet sale accounting criteria. We will account for the purchase of such securities and the repurchase agreement on a net basis and record a forward purchase commitment to purchase securities (each, a "Linked Transaction") at fair value on our consolidated balance sheets in the line item Linked Transactions, at fair value. Changes in the fair value of the assets and liabilities underlying the Linked Transactions and associated interest income and expense are reported as unrealized gain and net interest income on Linked Transactions, net on our consolidated statements of operations. If we subsequently finance the securities in a Linked Transaction with a different counterparty, we will regard it as an acquisition of a security and the repurchase financing as a collateralized financing transaction.
	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 the line item realized gain (loss) 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 (loss) 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.
	Income Taxes
	We have elected to be taxed as a REIT under the provisions of the Internal Revenue Code. In order to qualify as a REIT, we must annually distribute, in a timely manner to our stockholders, at least 90% of our taxable ordinary income. A REIT is not subject to tax on its earnings to the extent that it distributes its annual taxable income to its stockholders and as long as certain asset, income and stock ownership tests are met. We operate in a manner that will allow us to be taxed as a REIT. As permitted by the Internal Revenue Code, a REIT can designate dividends paid in the subsequent year as dividends of the current year if those dividends are both declared by the extended due date of the REIT's Federal income tax return and paid to stockholders by the last day of the subsequent year.
	As a REIT, if we fail to distribute in any calendar year at least the sum of (i) 85% of our ordinary income for such year, (ii) 95% of our capital gain net income for such year and (iii) any undistributed taxable income from the prior year, we would be subject to a non-deductible 4% excise tax on the excess of such required distribution over the sum of (a) the amounts actually distributed and (b) the amounts of income we retained and on which we have paid corporate income tax. Dividends declared by December 31 and paid by January 31 are treated as having been a distribution of our taxable income for the prior tax year.
	We and two of our domestic subsidiaries, American Capital Mortgage Investment TRS, LLC and Residential Credit Solutions, Inc., have made joint elections to treat the subsidiaries as taxable REIT subsidiaries. As such, American Capital Mortgage Investment TRS, LLC and Residential Credit Solutions, Inc. are subject to Federal, state and, if applicable, local income tax.
	We evaluate uncertain income tax positions, if any, in accordance with ASC Topic 740, Income Taxes ("ASC 740"). To the extent we incur interest and/or penalties in connection with our tax obligations, such amounts shall be classified as income tax expense on our consolidated statements of operations.
	Reclassifications
	Certain prior period amounts in the consolidated financial statements have been reclassified to conform to the current period presentation.
	Comparative Period Statement of Cash Flows
The Company removed non-cash components from two line items within the investing section of the previously reported consolidated statement of cash flows for the year ended December 31, 2012, with the effect of decreasing cash used for "purchases of agency securities" and an offsetting decrease in cash flows from "principal collection of agency securities."  These revisions do not affect the amounts previously reported as net cash provided by or used in operating activities, investing activities or financing activities, or the net change in cash and cash equivalents for any period and have no effect on the consolidated balance sheets or statements of operations or net asset value for any period. While the Company has concluded the revisions are not material to the previously reported financial statements, the Company has elected to revise its previously issued statement of cash flows for the year ended December 31, 2012 in this and future reports.

Agency_Securities

Agency Securities	12 Months Ended
	Dec. 31, 2013
Agency Securities [Abstract]	'
Agency Securities	'
	Agency Securities
	The following tables summarize our investments in agency RMBS as of December 31, 2013 and 2012 (dollars in thousands):
		December 31, 2013
		Fannie Mae				Freddie Mac				Ginnie Mae				Total
	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		)
	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		%
			December 31, 2013
			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
		31-Dec-12
		Fannie Mae				Freddie Mac				Total
	Fixed-rate agency RMBS:
	Par value	$	4,939,592			$	965,074			$	5,904,666
	Unamortized premium	271,729				53,375				325,104
	Amortized cost	5,211,321				1,018,449				6,229,770
	Gross unrealized gains	114,750				23,543				138,293
	Gross unrealized losses	(884		)		(137		)		(1,021		)
	Fixed-rate agency RMBS, at fair value	$	5,325,187			$	1,041,855			$	6,367,042
	Weighted average coupon as of December 31, 2012	3.4		%		3.57		%		3.43		%
	Weighted average yield as of December 31, 2012	2.42		%		2.65		%		2.46		%
	Weighted average yield for the year ended December 31, 2012	2.65		%		2.72		%		2.67		%
	As of December 31, 2012, all of our agency RMBS were fixed-rate securities.
	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 December 31, 2013 and 2012 according to their estimated weighted average life classification (dollars in thousands):
		December 31, 2013														December 31, 2012
	Weighted Average Life	Fair				Amortized				Weighted			Weighted Average Coupon			Fair				Amortized				Weighted		Weighted Average Coupon
		Value				Cost				Average						Value				Cost				Average
										Yield														Yield
	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	2,142,111				2,159,311				2.29	%		3.2	%		1,759,226				1,731,178				1.94	%	3.09	%
	Greater than five years and less than or equal to 10 years	3,485,241				3,646,188				2.72	%		3.43	%		4,484,509				4,375,925				2.66	%	3.57	%
	Greater than 10 years	5,241				5,600				2.96	%		3.5	%		123,307				122,667				2.52	%	3.12	%
	Total	$	5,641,682			$	5,820,194			2.56	%		3.35	%		$	6,367,042			$	6,229,770			2.46	%	3.43	%
	As of December 31, 2013 and 2012, none of our agency RMBS had an estimated weighted average life of less than 2.1 years and 3.4 years, respectively. As of December 31, 2013 and 2012, the estimated weighted average life of our agency security portfolio was 6.1 years and 7.0 years, respectively, which incorporates anticipated future prepayment assumptions. As of December 31, 2013 and 2012, our weighted average expected constant prepayment rate ("CPR") over the remaining life of our aggregate agency investment portfolio was 7% and 9%, 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 years ended December 31, 2013 and 2012 and for the period from commencement of operations on August 9, 2011 through December 31, 2011 (dollars in thousands):
			For the Year Ended December 31,								For the Period from August 9, 2011 (date operations commenced) through December 31, 2011
			2013				2012
	Proceeds from agency RMBS sold		$	7,817,303			$	4,163,571			$	712,191
	Increase (decrease) in receivable for agency RMBS sold		608,646				(271,849		)		271,849
	Less agency RMBS sold, at cost		(8,596,201		)		(3,818,112		)		(980,603		)
	Net realized gain (loss) on sale of agency RMBS		$	(170,252	)		$	73,610			$	3,437
	Gross realized gains on sale of agency RMBS		$	22,424			$	73,668			$	4,262
	Gross realized losses on sale of agency RMBS		(192,676		)		(58		)		(825		)
	Net realized gain (loss) on sale of agency RMBS		$	(170,252	)		$	73,610			$	3,437
	Pledged Assets
	The following tables summarize our agency RMBS pledged as collateral under repurchase agreements and derivative agreements by type as of December 31, 2013 and 2012 (dollars in thousands):
		December 31, 2013
	Agency RMBS Pledged (1)	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
	Under Derivative Agreements
Fair value	—				—				—				—
Accrued interest on pledged agency RMBS	—				—				—				—
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 pledged amounts of $583.2 million under repurchase agreements related to agency RMBS sold but not yet settled as of December 31, 2013.
	31-Dec-12
Agency RMBS Pledged	Fannie Mae				Freddie Mac				Total
Under Repurchase Agreements
Fair value	$	5,919,044			$	283,882			$	6,202,926
Accrued interest on pledged agency RMBS	15,662				774				16,436
Under Derivative Agreements
Fair value	68,072				5,995				74,067
Accrued interest on pledged agency RMBS	183				18				201
Total Fair Value of Agency RMBS Pledged and Accrued Interest	$	6,002,961			$	290,669			$	6,293,630
The following table summarizes our agency RMBS pledged as collateral under repurchase agreements by remaining maturity as of December 31, 2013 and 2012 (dollars in thousands):
	December 31, 2013												December 31, 2012
Remaining Maturity	Fair Value				Amortized				Accrued Interest on Pledged Agency RMBS				Fair Value				Amortized				Accrued Interest on Pledged Agency RMBS
					Cost												Cost
30 days or less	$	2,591,560			$	2,672,502			$	7,182			$	2,318,609			$	2,266,686			$	6,401
31 - 59 days	1,105,167				1,151,447				3,096				1,968,955				1,924,329				5,145
60 - 90 days	1,261,354				1,299,749				3,455				1,511,192				1,481,403				3,837
Greater than 90 days	660,654				673,560				1,714				404,170				396,497				1,053
Total	$	5,618,735			$	5,797,258			$	15,447			$	6,202,926			$	6,068,915			$	16,436
As of December 31, 2013 and 2012, none of our repurchase agreement borrowings backed by agency RMBS were due on demand or mature overnight.

NonAgency_Securities

Non-Agency Securities	12 Months Ended
	Dec. 31, 2013
Non-agency Securities [Abstract]	'
Non-Agency Securities	'
	Non-Agency Securities
	The following tables summarize our non-agency RMBS as of December 31, 2013 and 2012 (dollars in thousands):
	December 31, 2013
			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 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.
	31-Dec-12
			Fair				Gross Unrealized								Amortized Cost				Discount				Par/ Current Face				Weighted Average
	Category		Value				Gains				Losses																Coupon (1)			Yield
	Prime		$	113,351			$	10,338			$	—			$	103,013			$	(33,406	)		$	136,419			3.13	%		7.15	%
	Alt-A		403,522				30,325				(911		)		374,108				(226,224		)		600,332				2.02	%		7.36	%
	Option-ARM		68,861				12,761				—				56,100				(38,617		)		94,717				0.6	%		8.08	%
	Subprime		95,669				12,183				—				83,486				(130,937		)		214,423				0.38	%		7.92	%
	Total		$	681,403			$	65,607			$	(911	)		$	616,707			$	(429,184	)		$	1,045,891			1.7	%		7.47	%
	————————
	-1	Coupon rates are floating, except for $11.3 million and $18.6 million fair value of fixed-rate prime and Alt-A non-agency RMBS, respectively, as of December 31, 2012.
	The following table summarizes our non-agency RMBS at fair value, by their estimated weighted average life classifications as of December 31, 2013 and 2012 (dollars in thousands):
			December 31, 2013														31-Dec-12
	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		$	203,935			$	194,800			5.59	%		2.19	%		$	90,919			$	85,595			6.43	%		1.53	%
	> 5 to ≤ 7 years		211,013				195,913				6.84	%		2.38	%		266,090				240,472				7.24	%		2	%
	>7 years		596,269				536,418				7.7	%		1.08	%		324,394				290,640				7.96	%		1.55	%
	Total		$	1,011,217			$	927,131			7.07	%		1.46	%		$	681,403			$	616,707			7.47	%		1.7	%
	Our Prime non-agency RMBS include investments in securitization trusts issued between 2003 and 2013, with underlying prime mortgage loan collateral. Prime mortgage loans are residential mortgage loans that are considered to have the most stringent underwriting standards within the non-agency mortgage market, but do not carry any credit guarantee from either a U.S. Government agency or GSE. The loans backing securities with a combined fair value of $125.7 million issued prior to 2010 were originated during a period when underwriting standards were generally weak and housing prices have dropped significantly subsequent to their origination. As a result, there is still material credit risk embedded in these vintages. As of December 31, 2013, Prime securities include $69.8 million in fair value of securities issued during 2013, with underlying mortgage loans that were originated in a period of fairly stringent underwriting. In some cases these instruments are backed by Prime Jumbo loans and in other instances are GSE debt securities that contain structured credit risk issued by the GSE’s. As of December 31, 2013, our Prime securities have both floating-rate and fixed-rate coupons ranging from 1.0% to 6.5%, with weighted average coupons of underlying collateral ranging from 2.4% to 6.2%.
	Our Alt-A non-agency RMBS include senior tranches in securitization trusts issued between 2002 and 2007 and securities with Alt-A collateral that were re-securitized from 2010 to 2013. Alt-A, or alternative A-paper, mortgage loans are considered riskier than prime mortgage loans and less risky than sub-prime mortgage loans and 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 December 31, 2013, our Alt-A securities have both fixed and floating rate coupons ranging from 0.2% to 6.0% with weighted average coupons of underlying collateral ranging from 2.6% to 6.0%.
	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 December 31, 2013, 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 3.6%. The loans underlying our Option-ARM securities were originated between 2004 and 2007.
	Our Subprime non-agency RMBS issued prior to 2013 include 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 December 31, 2013, our Subprime securities issued prior to 2013 have floating rate coupons ranging from 0.2% to 4.9% and have underlying collateral with weighted-average coupons ranging from 4.0% to 7.9%. Additionally, we have classified certain non-performing loans that were securitized in 2013 as subprime securities. These 2013 securitizations are backed by loans originated from 1984 to 2011 and as of December 31, 2013, have a fair value of $33.5 million. As of December 31, 2013, our Subprime securities issued in 2013 have floating rate coupons ranging from 3.6% to 4.3% and have underlying collateral with weighted-average coupons ranging from 5.2% to 7.4%.
	More than 93% of our non-agency RMBS are rated below investment grade or have not been rated by credit agencies as of December 31, 2013.
	Realized Gains and Losses
	The following table summarizes our net realized gains and losses from the sale of non-agency RMBS during the years ended December 31, 2013 and 2012 (dollars in thousands):
			For the Year Ended December 31,
			2013				2012
	Proceeds from non-agency RMBS sold		$	197,259			$	32,341
	Less: non-agency RMBS sold, at cost		(180,403		)		(30,561		)
	Net realized gain on sale of non-agency RMBS		$	16,856			$	1,780
	Gross realized gain on sale of non-agency RMBS		$	18,790			$	1,780
	Gross realized loss on sale of non-agency RMBS		(1,934		)		—
	Net realized gain on sale of non-agency RMBS		$	16,856			$	1,780
	Pledged Assets
	Non-agency RMBS with a fair value of $899.2 million and $545.7 million were pledged as collateral under repurchase agreements as of December 31, 2013 and 2012, respectively. As of December 31, 2013 and 2012, 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 December 31, 2013 and 2012 (dollars in thousands):
		December 31, 2013												December 31, 2012
	Remaining Maturity	Fair Value				Amortized				Accrued Interest on Pledged Non-Agency RMBS				Fair Value				Amortized				Accrued Interest on Pledged Non-Agency RMBS
						Cost												Cost
	30 days or less	$	547,087			$	502,063			$	857			$	315,332			$	291,378			$	741
	31 - 59 days	70,478				68,622				57				141,508				122,103				231
	60 - 90 days	64,873				58,091				55				88,825				79,782				167
	Greater than 90 days	216,738				196,644				242				—				—				—
	Total	$	899,176			$	825,420			$	1,211			$	545,665			$	493,263			$	1,139

Repurchase_Agreements

Repurchase Agreements	12 Months Ended
	Dec. 31, 2013
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 December 31, 2013 and 2012, 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.
	The following table summarizes our borrowings under repurchase arrangements and weighted average interest rates classified by remaining maturities as of December 31, 2013 and 2012 (dollars in thousands):
		December 31, 2013					December 31, 2012
				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	$	3,047,986	0.6	%	14	$	2,547,674	0.61	%	19
	> 1 to ≤ 2 months	816,960		0.55	%	45	2,035,551		0.56	%	46
	> 2 to ≤ 3 months	1,506,888		0.52	%	77	1,315,109		0.54	%	76
	> 3 to ≤ 6 months	621,124		0.54	%	135	243,877		0.51	%	143
	> 6 to ≤ 9 months	147,729		0.49	%	249	14,317		0.62	%	269
	> 9 to ≤ 12 months	191,991		0.5	%	321	89,263		0.62	%	319
	> 12 months	250,000		0.59	%	853	—		—	%	—
	Total	6,582,678		0.56	%	90	6,245,791		0.57	%	50
	U.S. Treasury repurchase agreements
	Short-term	575,514		0.07	%	2	—		—	%	—
	Total repurchase agreements	$	7,158,192	0.52	%	83	$	6,245,791	0.57	%	50
	We had repurchase agreements with 31 and 29 financial institutions as of December 31, 2013 and 2012, respectively. In addition, less than 7% and 8% 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 25% and 26% of our equity at risk as of December 31, 2013 and 2012, respectively.
	We had agency RMBS with fair values of $5.6 billion and $6.2 billion and non-agency RMBS with fair values of $899.2 million and $545.7 million pledged as collateral against repurchase agreements, as of December 31, 2013 and 2012, respectively. Agency RMBS pledged do not include $583.2 million pledged under repurchase agreements related to securities sold but not yet settled as of December 31, 2013. As of December 31, 2013, borrowings of $5.9 billion and $647.1 million, with weighted average remaining days to maturity of 96 and 33, were secured by agency and non-agency RMBS, respectively.

Derivatives

Derivatives	12 Months Ended
	Dec. 31, 2013
Derivative Instruments [Abstract]	'
Derivative Instruments and Hedging Activities Disclosure [Text Block]	'
	Derivatives and Other Securities
	In connection with our risk management strategy, we economically 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 2- Summary of Significant Accounting Policies.
	The table below presents the balance sheet location and fair value information for our derivatives outstanding as of December 31, 2013 and 2012 (in thousands):
			December 31,
			2013				2012
	Interest rate swaps		$	51,957			$	519
	Interest rate swaptions		50,009				21,944
	U.S. Treasury futures		3,399				—
	TBA securities		2,856				580
	Derivative assets, at fair value		$	108,221			$	23,043
	Interest rate swaps		$	9,490			$	60,188
	TBA securities		1,837				3,538
	Derivative liabilities, at fair value		$	11,327			$	63,726
	The following table summarizes the effect of our outstanding derivatives and other securities on our consolidated statements of operations during the years ended December 31, 2013 and 2012 (in thousands):
			For the Year Ended December 31,
			2013										2012
			Realized Loss on Periodic Settlements of Interest Rate Swaps, net			Realized Gain (Loss) 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 (Loss) on Other Derivatives and Securities, net			Unrealized Gain (Loss) on Other Derivatives and Securities, net			Unrealized Gain and
																						Net Interest Income on Linked Transactions, net
	Interest rate swaps		$	(41,006	)	$	101,297		$	97,769			$	(18,458	)	$	(22,560	)	$	(48,930	)	$	—
	Interest rate swaptions		—			18,558			11,550				—			(1,725		)	(5,207		)	—
	TBA securities		—			(47,063		)	3,933				—			(14,057		)	(1,648		)	—
	U.S. Treasuries		—			(12,952		)	(11,862		)		—			(200		)	—			—
	U.S. Treasury futures		—			6,322			3,399				—			—			—			—
	Short sales of U.S. Treasuries		—			45,434			3,259				—			(8,206		)	(2,884		)	—
	REIT equity investments		—			977			(502		)		—			—			—			—
	Linked Transactions		—			—			—				—			—			—			3,384
	Total		$	(41,006	)	$	112,573		$	107,546			$	(18,458	)	$	(46,748	)	$	(58,669	)	$	3,384
	The following tables summarize changes in notional amounts for our outstanding derivatives and other securities for the years ended December 31, 2013 and 2012 and for the period from commencement of operations on August 9, 2011 through December 31, 2011 (in thousands):
		31-Dec-12				Additions/ Long Positions			Expirations/			31-Dec-13
		Notional							Terminations/ Short Positions			Notional
		Amount										Amount
	Interest rate swaps	$	2,940,000			4,225,000			(3,925,000	)		$	3,240,000
	Interest rate swaptions	$	1,150,000			2,150,000			(1,200,000	)		$	2,100,000
	TBA securities	$	(522,188	)		3,295,280			(3,546,908	)		$	(773,816	)
	U.S. Treasuries	$	—			3,709,500			(3,053,500	)		$	656,000
	U.S. Treasury futures	$	—			650,000			(800,000	)		$	(150,000	)
	Short sales of U.S. Treasuries	$	(425,000	)		4,983,500			(4,581,500	)		$	(23,000	)
		31-Dec-11				Additions/ Long Positions			Expirations/			31-Dec-12
		Notional							Terminations/ Short Positions			Notional
		Amount										Amount
	Interest rate swaps	$	875,000			2,890,000			(825,000	)		$	2,940,000
	Interest rate swaptions	$	50,000			1,325,000			(225,000	)		$	1,150,000
	TBA securities	$	(101,000	)		7,233,405			(7,654,593	)		$	(522,188	)
	U.S. Treasuries	$	—			130,000			(130,000	)		$	—
	Short sales of U.S. Treasuries	$	(50,000	)		3,216,000			(3,591,000	)		$	(425,000	)
	Linked Transactions (1)	$	88,671			10,920			(99,591	)		$	—
		9-Aug-11				Additions/ Long Positions			Expirations/			31-Dec-11
		Notional							Terminations/ Short Positions			Notional
		Amount										Amount
	Interest rate swaps	$	—			875,000			—			$	875,000
	Interest rate swaptions	$	—			50,000			—			$	50,000
	TBA securities	$	—			234,000			(335,000	)		$	(101,000	)
	U.S. Treasuries	$	—			190,000			(190,000	)		$	—
	Short sales of U.S. Treasuries	$	—			540,000			(590,000	)		$	(50,000	)
	Linked Transactions (1)	$	—			90,385			(1,714	)		$	88,671
	————————
	-1	The notional amount of Linked Transactions is represented by the current face amount of the underlying securities.
	Interest Rate Swap Agreements
	As of December 31, 2013 and 2012, 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 December 31, 2013 and 2012, we had interest rate swap agreements summarized in the tables below (dollars in thousands).
					December 31,
					2013								2012
	Interest Rate Swaps		Balance Sheet Location		Notional Amount				Fair Value				Notional Amount				Fair Value
	Interest rate swap assets		Derivative assets, at fair value		$	2,275,000			$	51,957			$	50,000			$	519
Interest rate swap liabilities		Derivative liabilities, at fair value		965,000				(9,490		)		2,890,000				(60,188		)
				$	3,240,000			$	42,467			$	2,940,000			$	(59,669	)
December 31, 2013
		Notional				Fair Value				Weighted Average
		Amount
Current Maturity Date for Interest Rate Swaps (1)										Fixed			Receive			Maturity
										Pay Rate			Rate (2)			(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
December 31, 2012
		Notional				Fair Value				Weighted Average
Current Maturity Date for Interest Rate Swaps (3)		Amount								Fixed			Receive			Maturity
										Pay Rate			Rate (2)			(Years)
≤ 3 years		$	550,000			$	(6,639	)		0.81	%		0.31	%		2.3
> 3 to ≤ 5 years		1,215,000				(24,297		)		1.17	%		0.32	%		4.5
> 5 to ≤ 7 years		550,000				(16,256		)		1.55	%		0.34	%		6.4
> 7 years		625,000				(12,477		)		1.89	%		0.34	%		9.5
Total		$	2,940,000			$	(59,669	)		1.33	%		0.32	%		5.5
————————
(1)	Includes swaps with an aggregate notional of $1.2 billion with deferred start dates averaging 1.9 years from December 31, 2013.
(2)	Weighted average receive rate excludes impact of $1.2 billion of forward starting interest rate swaps.
(3)	Includes swaps with an aggregate notional of $50.0 million with deferred start dates within four months from December 31, 2012.
Interest rate swaps with a notional amount of $1.3 billion and asset fair value of $21.4 million as of December 31, 2013 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 December 31, 2013 and 2012 (dollars in thousands):
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
December 31, 2012
		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		$	2,156			$	2			0.2		$	125,000			3.3	%		10
> 3 to ≤ 12 months		635				3				0.3		50,000				2.68	%		7
>12 to ≤ 24 months		4,117				1,820				1.5		250,000				2.67	%		6.4
> 24 months		20,298				20,119				3.2		725,000				3.27	%		8.1
Total / weighted average		$	27,206			$	21,944			2.4		$	1,150,000			3.12	%		7.9
TBA Securities
As of December 31, 2013 and 2012, we had contracts to purchase ("long position") and sell ("short position") TBA securities on a forward basis, presented in the following table (in thousands):
		December 31,
		2013								2012
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		$	210,600			$	158			$	182,600			$	580
Sale of TBA securities		(463,496		)		2,698				—				—
Total TBA assets		(252,896		)		2,856				182,600				580
TBA liabilities
Purchase of TBA securities		—				—				572,134				(992		)
Sale of TBA securities		(520,920		)		(1,837		)		(1,276,922		)		(2,546		)
Total TBA liabilities		(520,920		)		(1,837		)		(704,788		)		(3,538		)
Total net TBA		$	(773,816	)		$	1,019			$	(522,188	)		$	(2,958	)
————————
(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.
Linked Transactions
Our Linked Transactions are evaluated on a combined basis, reported as forward (derivative) instruments on our consolidated balance sheets at fair value.  The fair value of Linked Transactions reflect the value of the underlying non-agency RMBS, net of repurchase agreement borrowings and accrued interest receivable and payable on such instruments.  The change in the fair value of our Linked Transactions is reported as unrealized gain (loss) and net interest income on Linked Transactions, net, a component of other gain (loss), net in our consolidated statements of operations.
The following table presents the composition of unrealized gain (loss) and net interest income on Linked Transactions, net during the years ended December 31, 2013 and 2012 and for the period from commencement of operations on August 9, 2011 through December 31, 2011 (in thousands):
		For the Year Ended December 31,								For the Period from August 9, 2011 (date operations commenced) through December 31, 2011
		2013				2012
Coupon interest income		$	—			$	302			$	457
Discount accretion		—				590				553
Interest expense		—				(183		)		(202		)
Unrealized gain, net		—				2,675				(1,858		)
Unrealized gain (loss) and net interest income on Linked Transactions, net		$	—			$	3,384			$	(1,050	)
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 $637.3 million and a face amount of $656.0 million as of December 31, 2013, which is presented as U.S. 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 $3.4 million and a notional amount of $(150.0) million as of 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 $22.5 million and $421.1 million as of December 31, 2013 and 2012, respectively. The borrowed securities were collateralized by cash payments of $22.7 million and $418.9 million as of December 31, 2013 and 2012, 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. Any changes in fair value of these investments are presented in unrealized gain (loss) on other derivatives and securities, net in our consolidated statements of operations. For the year ended December 31, 2013, these investments had a net unrealized loss of $(0.5) million and $1.0 million in dividend income, which is included in realized gain (loss) 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 and central clearing exchange 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 December 31, 2013, 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.
We did not have an amount at risk with any counterparty related to our non-centrally cleared interest rate swap and swaption agreements greater than 2% and 1% of our stockholders’ equity, as of December 31, 2013 and 2012, respectively.
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)	12 Months Ended
	Dec. 31, 2013
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 December 31, 2013 and 2012 (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
	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
	December 31, 2012
	Interest rate swaps and swaptions (1)		$	22,463	$	—	$	22,463	$	(13,250	)	$	—		$	9,213
	Receivable under reverse repurchase agreements		418,888		—		418,888		(418,888		)	—			—
	Total		$	441,351	$	—	$	441,351	$	(432,138	)	$	—		$	9,213
	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
	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	)	$	—
	December 31, 2012
	Interest rate swaps (1)		$	60,188	$	—	$	60,188	$	(13,250	)	$	(46,938	)	$	—
	Repurchase agreements		6,245,791		—		6,245,791		(418,888		)	(5,826,903		)	—
	Total		$	6,305,979	$	—	$	6,305,979	$	(432,138	)	$	(5,873,841	)	$	—
	————————
	-1	Reported under derivative assets / liabilities, at fair value in the accompanying consolidated balance sheets. Refer to Note 6 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 3 and 4 for additional information regarding assets pledged as collateral.

Fair_Value_Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2013
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 an 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 cash flow models that are primarily based on observable market-based inputs but also include unobservable market data inputs (including prepayment speeds, delinquency levels and discount rates). Our MSR are a component of other assets on the consolidated balance sheets.
	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 December 31, 2013 and 2012, on the consolidated balance sheets by the valuation hierarchy, as described above (in thousands):
			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
	Mortgage servicing rights		—			—			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 repurchase agreements		22,530			—			—			22,530
	Mortgage servicing liability		—			—			15,608			15,608
	Total		$	22,530		$	11,327		$	15,608		$	49,465
			December 31, 2012
			Level 1			Level 2			Level 3			Total
	Assets
	Agency RMBS		$	—		$	6,367,042		$	—		$	6,367,042
	Non-agency RMBS		—			585,734			95,669			681,403
	Derivative assets		—			23,043			—			23,043
	Total		$	—		$	6,975,819		$	95,669		$	7,071,488
	Liabilities
	Derivative liabilities		$	—		$	63,726		$	—		$	63,726
	Obligation to return securities borrowed under repurchase agreements		421,077			—			—			421,077
	Total		$	421,077		$	63,726		$	—		$	484,803
	The following tables present a summary of the changes in fair value for Level 3 assets carried at fair value as of December 31, 2013 and 2012 (in thousands):
			For the Year Ended December 31, 2013
			MSR			Non-Agency RMBS			Total
	Balance as of December 31, 2012		$	—		$	95,669		$	95,669
	Unrealized gain		—			10,073			10,073
	Unrealized loss		(117		)	(6,971		)	(7,088		)
	Total unrealized gain (loss), net		(117		)	3,102			2,985
	Purchases		15,725			60,115			75,840
	Sales of securities		—			(6,293		)	(6,293		)
	Principal repayments on securities		—			(9,010		)	(9,010		)
	Discount accretion		—			5,694			5,694
	Transfer out of Level 3		—			(149,277		)	(149,277		)
	Balance as of December 31, 2013		$	15,608		$	—		$	15,608
	Unrealized loss related to Level 3 assets held as of December 31, 2013		$	(117	)	$	—		$	—
			For the Year Ended December 31, 2012
			Non-Agency RMBS			Linked Transactions			Total
	Balance as of December 31, 2011		$	5,969		$	1,746		$	7,715
	Unrealized gain		13,975			827			14,802
	Unrealized loss		(723		)	—			(723		)
	Total unrealized gain, net		13,252			827			14,079
	Purchases of securities		75,102			—			75,102
	Principal repayments on securities		(9,641		)	(291		)	(9,932		)
	Securities recorded upon de-linking of Linked Transactions		7,893			(7,893		)	—
	Net change in borrowings underlying Linked Transactions		—			5,445			5,445
	Discount accretion		3,094			159			3,253
	Accrued interest on Linked Transactions		—			7			7
	Balance as of December 31, 2012		$	95,669		$	—		$	95,669
Unrealized gain related to Level 3 assets held as of December 31, 2012		$	13,252		$	827		$	14,079
During the year ended December 31, 2013, we transferred $149.3 million of subprime non-agency RMBS from Level 3 to Level 2. The assets were deemed to be Level 2 based on the availability of third-party pricing and corroborating market information. Transfers between levels are deemed to take place on the first day of the reporting period in which the transfer occurred.
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. We estimate the fair value of our REIT equity securities on a market approach using Level 1 inputs based on quoted market prices.
The Company used a third-party pricing provider in the fair value measurement of its Level 3 MSR. The significant unobservable inputs used in estimating the fair value measurement of our Level 3 MSR asset and liability 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 prepayment rates and delinquency rates, together with the discount rate used by a third-party pricing provider in estimating the fair value of our Level 3 MSR with fair values totaling $15.6 million as of December 31, 2013, respectively:
		December 31, 2013
Unobservable Level 3 Input		Minimum		Weighted	Maximum
				Average
Constant prepayment rate		6%		15%	35%
Delinquency rate		—%		8%	29%
Discount rate		16%		16%	16%
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 the probability of delinquency and a directionally opposite change in the assumption used for prepayment rates. However, given the interrelationship between delinquency and prepayment rate estimates and the discount rate, overall MSR market conditions would likely have a more significant impact on our Level 3 fair values than changes in any one unobservable input.
For information regarding valuation of our derivative instruments, please refer to the discussion of derivative and other hedging instruments in Note 2. 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.

Other_Assets_Notes

Other Assets (Notes)	12 Months Ended
	Dec. 31, 2013
Other Assets [Abstract]	'
Other Assets Disclosure [Text Block]	'
	Other Assets
	The following table summarizes our other assets as of December 31, 2013 and 2012 (dollars in thousands):
			December 31,
			2013 (1)			2012
	Property and equipment, at cost		$	4,024		$	—
	Accumulated depreciation		(164		)	—
	Net property and equipment		3,860			—
	Servicing advances		33,358			—
	Mortgage servicing rights, at fair value		15,608			—
	Prepaid expenses		6,978			512
	Intangible assets		17,000			—
	Other		4,387			1,180
	Total other assets		$	81,191		$	1,692
	——————
	-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, subject to change as the Company finalizes its valuation. The fair values of the assets acquired on November 27, 2013 closely approximate the carrying values as December 31, 3013.
	Servicing Advances
	We are required to fund cash advances in connection with our servicing operations. These advances are reported as servicing advances within the other assets line item on the consolidated balance sheets and represent advances for principal and interest, property taxes and insurance, as well as other reasonable out-of-pocket expenses incurred by the Company in the performance of its servicing obligations.
	Mortgage Servicing Rights
	Our $15.6 million balance of MSR as of December 31, 2013 is related to RCS's 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 for adequate compensation. These transfers do not qualify for sale accounting and are treated as financing arrangements, under which we recognize both MSR assets and MSR financing liabilities. We have elected the option to account for both the MSR assets and MSR liabilities at estimated fair value with changes in fair value reported in net income. The following table summarizes activity related to MSR for the year ended December 31, 2013 (dollars in thousands):
			For the Year Ended December 31, 2013
	Balance at beginning of period		$	—
	Additions		15,725
	Changes in fair value due to
	Changes in fair value assumptions		—
	Other changes in fair value		(117		)
	Balance at end of period		$	15,608
	The following table presents the components of servicing and other operating income and expenses for the year ended December 31, 2013 (dollars in thousands):
			For the Year Ended December 31, 2013
	Servicing fee income		$	2,603
	Ancillary and incentive income		735
	Other income		12
	Servicing and other operating income		$	3,350
	Acquisition related costs		$	3,055
	Employee costs		2,845
	Other servicing costs		1,589
	Servicing and other operating expenses		$	7,489

Other_Liabilities_Notes

Other Liabilities (Notes)	12 Months Ended
	Dec. 31, 2013
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 December 31, 2013 and 2012 (dollars in thousands):
			December 31,
			2013 (2)		2012
	Cash collateral held on derivatives		$	32,463	$	—
	Due to manager		1,885		1,162
	Payable for equity securities purchased		4,581		—
	Accrued interest		4,401		5,009
	Mortgage servicing liability, at fair value (1)		15,608		—
	Excise tax payable		574		1,172
	Other accounts payable and accrued expenses		10,203		273
	Total accounts payable and other accrued liabilities		$	69,715	$	7,616
	——————
	-1	Mortgage servicing liability represents our obligations associated with excess MSR transferred to to a third party which are accounted for as financing arrangements. We have elected the option to account for MSR liabilities at estimated fair value with changes in fair value reported in net income.
	-2	Certain amounts within accounts payable and other accrued liabilities relate to our acquisition of RCS and were recorded at fair value as of the transaction date on a provisional basis, subject to change as the Company finalizes its valuation. The fair values of the liabilities assumed on November 27, 2013 closely approximate the carrying values as December 31, 3013.

Stockholders_Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2013
Class of Stock [Line Items]	'
Stockholders' Equity Note Disclosure [Text Block]	'
	Stockholders’ Equity
	Equity Offerings
	During the years ended December 31, 2013 and 2012, we issued the following shares of common stock (amounts in thousands except per share amounts):
	Public Offering Date		Price Received Per Share (1)		Number of Shares	Net Proceeds (2)
	Feb-13		$	25.4	23,000	$	583,915
	Total		$	25.4	23,000	$	583,915
	Mar-12		$	21.55	13,600	$	292,780
	May-12		22.74		12,650	287,151
	Total		$	22.09	26,250	$	579,931
	——————
	-1	Price received per share is net of underwriters' discount, if applicable.
	(2)	Net Proceeds are net of any underwriters' discount and other offering costs.
	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.
	During the year ended December 31, 2013, we repurchased approximately 7.6 million shares of our common stock at an average repurchase price of $20.23 per share, including expenses, totaling $154.1 million. During the year ended December 31, 2012, we repurchased 0.3 million shares of our common stock at an average repurchase price of $22.76 per share, including expenses, totaling $6.8 million. As of December 31, 2013, we had an additional $139.1 million available under current Board authorization for repurchases of our common stock through December 31, 2014.
	Long-Term Incentive Plan
	We sponsor an equity incentive plan to provide for the issuance of equity-based awards, including stock options, restricted stock, restricted stock units and unrestricted stock to our independent directors. Following the completion of our IPO, we granted 1,500 shares of restricted common stock to each of our four independent directors for a total of 6,000 shares of restricted common stock with a grant date fair value of $20.00 per share. These shares will vest equally over a three-year period, subject to their continued service on our board of directors. For the years ended December 31, 2013 and 2012, we granted 1,500 shares of restricted stock to each independent director, or a total of 7,500 and 6,000 shares, with a weighted average grant date fair value of $25.23 and $19.67 per share, respectively. As of December 31, 2013, we had 80,500 shares of common stock reserved for future issuance under our long-term incentive plan. As of December 31, 2013 and 2012, we had unrecognized compensation expense of $0.2 million and $0.1 million related to unvested shares of restricted stock, respectively. We recorded compensation expense of $0.1 million, $0.1 million and $16 thousand related to restricted stock awards for the years ended December 31, 2013 and 2012 and for the period from commencement of operations on August 9, 2011 through December 31, 2011, respectively.
	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 year ended December 31, 2013.

Income_Taxes_Notes

Income Taxes (Notes)	12 Months Ended
	Dec. 31, 2013
Dividends [Abstract]	'
Income Tax Disclosure [Text Block]	'
	Note 12. Income Taxes
	The following table summarizes dividends declared the years ended December 31, 2013 and 2012 and for the period from commencement of operations on August 9, 2011 through December 31, 2011and their related tax characterization.
				Tax Characterization of Dividends
	Year	Dividends Declared Per Share		Ordinary Income		Long-Term Capital Gains Per Share
				Per Share
	2013	$	3.05	$	3.05	$	—
	2012	$	3.6	$	3.6	$	—
	2011	$	1	$	1	$	—
	As of December 31, 2013, we had undistributed taxable income of $39.8 million that we expect to declare by the extended due date of our 2013 Federal income tax return and pay in 2014. For the years ended December 31, 2013 and 2012 and for the period from commencement of operations on August 9, 2011 through December 31, 2011, we did not distribute the required minimum amount of taxable income pursuant to Federal excise tax requirements, as described in Note 2. As such, we accrued an excise tax on the accompanying consolidated statements of operations of $0.7 million, $1.2 million and $32 thousand for the years ended December 31, 2013 and 2012 and for the period from commencement of operations on August 9, 2011 through December 31, 2011, respectively. However, we do not expect to incur any additional income tax liability on our 2013 taxable income.
	Based on our analysis of any potential uncertain income tax positions, we concluded that we do not have any uncertain tax positions that meet the recognition or measurement criteria as of December 31, 2013 and 2012. Our tax returns for tax years 2011 through 2012 are open to examination by the IRS. In the event that we incur income tax related interest and penalties, our policy is to classify them as a component of provision for income taxes.
	We acquired 100% of RCS, a taxable subchapter C corporation, on November 27, 2013, with which we filed a joint TRS election. As of December 31, 2013, RCS had Federal net operating loss ("NOL") carryforwards of approximately $(50.0) million which can be carried forward for up to twenty years. As a result of the change in ownership, the utilization of most of the NOL is subject to limitations imposed by the Internal Revenue Code. The gross deferred tax assets associated with the NOL and other temporary differences as of December 31, 2013 were approximately $21.0 million, with respect to which, RCS has provided a full valuation allowance.

Management_Fees_and_Related_Pa

Management Fees and Related Parties (Notes)	12 Months Ended
	Dec. 31, 2013
Related Party Transaction [Line Items]	'
Related Party Transactions Disclosure [Text Block]	'
	Note 11. Management Agreement and Related Parties
	We have entered into a management agreement with our Manager with a current renewal term through August 9, 2014 and automatic one-year extension options thereafter. The management agreement may only be terminated by either us or our Manager without cause, as defined in the management agreement, after the completion of the current renewal term, or the expiration of any automatic subsequent renewal term, provided that either party provide 180-days prior written notice of non-renewal of the management agreement. If we were not to renew the management agreement without cause, we must pay a termination fee on the last day of the applicable term, equal to three times the average annual management fee earned by our Manager during the prior 24-month period immediately preceding the most recently completed month prior to the effective date of termination. We may only not renew the management agreement with or without cause with the consent of a majority of our independent directors. Our Manager is responsible for, among other things, performing all of our day-to-day functions, determining investment criteria in conjunction with our Board of Directors, sourcing, analyzing and executing investments, asset sales and financings and performing asset management duties.
	We pay our Manager a base management fee payable monthly in arrears in an amount equal to one twelfth of 1.50% of our Equity. Our Equity is defined as our month-end stockholders' equity, adjusted to exclude the effect of any unrealized gains or losses included in retained earnings, each as computed in accordance with GAAP. There is no incentive compensation payable to our Manager pursuant to the management agreement. We recorded an expense for management fees of $18.7 million, $9.6 million and $1.2 million for the years ended December 31, 2013 and 2012 and for the period from commencement of operations on August 9, 2011 through December 31, 2011, respectively, of which $1.4 million and $1.0 million are included in accounts payable and other accrued liabilities on the consolidated balance sheet as of December 31, 2013 and 2012, respectively.
	In addition, we reimburse our Manager for expenses directly related to our operations, excluding employment-related expenses of our Manager, American Capital and its other affiliates who provide services to us pursuant to the management agreement. We recorded expense reimbursements to our Manager of $1.8 million, $1.3 million and $0.3 million for the years ended December 31, 2013 and 2012 and for the period from commencement of operations on August 9, 2011 through December 31, 2011, respectively, of which $0.1 million and $0.2 million is included in accounts payable and other accrued liabilities on the consolidated balance sheet as of December 31, 2013 and 2012, respectively, consisting mostly of information technology systems.
	As of December 31, 2013, American Capital does not hold any shares of our common stock.
	The sister company of our Manager is the external manager of American Capital Agency Corp., a publicly-traded REIT that invests in agency mortgage investments. All of our officers and the members of our mortgage investment team and other support personnel are employees of either the parent company of our Manager or American Capital. Because neither we nor our Manager have any employees other than those at RCS, our Manager has entered into an administrative services agreement with American Capital and the parent company of our Manager, pursuant to which our Manager has access to their employees, infrastructure, business relationships, management expertise, information technologies, capital raising capabilities, legal and compliance functions, and accounting, treasury and investor relations capabilities, to enable our Manager to fulfill all of its responsibilities under the management agreement. We are not a party to the administrative services agreement.

Quarterly_Results_Notes

Quarterly Results (Notes)	12 Months Ended
	Dec. 31, 2013
Quarterly Results [Abstract]	'
Quarterly Financial Information [Text Block]	'
	Note 14. Quarterly Results (Unaudited)
	The following is a presentation of the quarterly results of operations for the years ended December 31, 2013 and 2012 (in thousands, except per share data).
		For the Three Months Ended
		31-Dec-13			30-Sep-13			30-Jun-13			31-Mar-13
	Interest income	$	69,694		$	70,511		$	63,927		$	51,567
	Interest expense	(10,656		)	(10,949		)	(9,113		)	(8,036		)
	Net interest income	59,038			59,562			54,814			43,531
	Total other losses, net	(62,310		)	(39,154		)	(102,160		)	(63,702		)
	Total expenses	13,676			6,506			7,007			6,221
	Income (loss) before excise tax	(16,948		)	13,902			(54,353		)	(26,392		)
	Excise tax	302			200			—			177
	Net income (loss)	$	(17,250	)	$	13,702		$	(54,353	)	$	(26,569	)
	Net income (loss) per common share—basic and diluted	$	(0.33	)	$	0.25		$	(0.94	)	$	(0.56	)
	Weighted average number of common shares outstanding—basic and diluted	52,028			54,515			57,982			47,469
	Dividends declared per common share	$	0.65		$	0.7		$	0.8		$	0.9
		For the Three Months Ended
		31-Dec-12			30-Sep-12			30-Jun-12			31-Mar-12
	Interest income	$	49,768		$	44,355		$	34,695		$	16,602
	Interest expense	(8,288		)	(7,329		)	(4,786		)	(1,664		)
	Net interest income	41,480			37,026			29,909			14,938
	Total other gains, net	14,164			114,008			5,985			8,508
	Total expenses	4,514			4,360			3,665			2,117
	Income before excise tax	51,130			146,674			32,229			21,329
	Excise tax	741			432			—			9
	Net income	$	50,389		$	146,242		$	32,229		$	21,320
	Net income per common share—basic and diluted	$	1.4		$	4.03		$	1.15		$	1.82
	Weighted average number of common shares outstanding—basic and diluted	36,105			36,262			28,129			11,724
	Dividends declared per common share	$	0.9		$	0.9		$	0.9		$	0.9

Policies

(Policies)	12 Months Ended
	Dec. 31, 2013
Fair Value of Financial Assets [Abstract]	'
Basis of Presentation and Significant Accounting Policies [Text Block]	'
	Basis of Presentation and Consolidation
	The consolidated financial statements of the Company are prepared in accordance with U.S. generally accepted accounting principles ("GAAP"). Our consolidated financial statements include the accounts of our wholly-owned taxable REIT subsidiaries, American Capital Mortgage Investment TRS, LLC and RCS. Significant intercompany accounts and transactions have been eliminated.
Use of Estimates, Policy [Policy Text Block]	'
	Use of Estimates
	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, disclosure of contingent assets and liabilities at the date of the financial statements and revenues and expenses during the period reported. Actual results could differ from those estimates.
Earnings Per Share, Policy [Policy Text Block]	'
	Earnings per Share
	Basic earnings per share ("EPS") is computed by dividing net income by the weighted average number of common shares outstanding during the period. Diluted EPS assumes the conversion, exercise or issuance of all potential common stock equivalents unless the effect is to reduce a loss or increase the income per share.
Cash and Cash Equivalents, Policy [Policy Text Block]	'
	Cash and Cash Equivalents
	Cash and cash equivalents consist of unrestricted demand deposits and highly liquid investments with original maturities of three months or less. Cash and cash equivalents are carried at cost, which approximates fair value.
Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block]	'
	Restricted Cash and Cash Equivalents
	Restricted cash includes cash pledged as collateral for clearing and executing trades, interest rate swaps and repurchase agreements. Restricted cash is carried at cost, which approximates fair value.
Fair Value of Financial Instruments, Policy	'
	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 economic hedging instruments. See Note 8 - Fair Value Measurements.
Interest Income	'
	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 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
	The Company’s MSR represent the right to service mortgage loans in return for a servicing fee. The Company 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. These advances are reported as servicing advances within the other assets line item on the consolidated balance sheets.
	MSR are reported at fair value within the other assets line item on the consolidated balance sheets. Changes in the fair value of MSR as well as servicing fee income are reported within servicing and other income on the consolidated statements of operations. The related servicing expenses are recorded in servicing and other operating expenses on the consolidated statements of operations. See Note 9 - Other Assets 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 for adequate compensation, 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 any MSR financing liabilities at estimated fair value, with changes in fair value reflected in income during the period in which they occur. See Note 10 - Accounts Payable and Other Accrued Liabilities for the presentations of our mortgage servicing liability.
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 (loss) on other derivatives and securities, net.
Repurchase Agreements, Valuation	'
	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, other than those treated as Linked Transactions (see Derivatives below), 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
	We from time to time borrow securities to cover short sales of U.S. Treasury securities through reverse repurchase transactions under our master repurchase agreements (see Derivatives Instruments below). We account for these as securities borrowing transactions and recognize an obligation to return the borrowed securities at fair value on the balance sheet 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.
Management and Investment Advisory Fees, Policy [Policy Text Block]	'
	Manager Compensation
	The management agreement provides for the payment to our Manager of a management fee and reimbursement of certain operating expenses, which are accrued and expensed during the period for which they are earned or incurred. Refer to Note 11 for disclosure on the terms of the management agreement.
Derivatives	'
	Derivatives
	We maintain 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 also may 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 both our own and our counterparties’ 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 risk is not significant to the overall valuation of these agreements.
	The payment of periodic settlements of net interest on interest rate swaps are 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 (loss) 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 (loss) 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 (loss) 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 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 (loss) 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.
	Linked Transactions
	If we finance the purchase of securities with repurchase agreements with the same counterparty from whom the securities are purchased and both transactions are entered into contemporaneously or in contemplation of each other, the transactions are presumed not to meet sale accounting criteria. We will account for the purchase of such securities and the repurchase agreement on a net basis and record a forward purchase commitment to purchase securities (each, a "Linked Transaction") at fair value on our consolidated balance sheets in the line item Linked Transactions, at fair value. Changes in the fair value of the assets and liabilities underlying the Linked Transactions and associated interest income and expense are reported as unrealized gain and net interest income on Linked Transactions, net on our consolidated statements of operations. If we subsequently finance the securities in a Linked Transaction with a different counterparty, we will regard it as an acquisition of a security and the repurchase financing as a collateralized financing transaction.
	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 the line item realized gain (loss) 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 (loss) 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.
Income Tax, Policy [Policy Text Block]	'
	Income Taxes
	We have elected to be taxed as a REIT under the provisions of the Internal Revenue Code. In order to qualify as a REIT, we must annually distribute, in a timely manner to our stockholders, at least 90% of our taxable ordinary income. A REIT is not subject to tax on its earnings to the extent that it distributes its annual taxable income to its stockholders and as long as certain asset, income and stock ownership tests are met. We operate in a manner that will allow us to be taxed as a REIT. As permitted by the Internal Revenue Code, a REIT can designate dividends paid in the subsequent year as dividends of the current year if those dividends are both declared by the extended due date of the REIT's Federal income tax return and paid to stockholders by the last day of the subsequent year.
	As a REIT, if we fail to distribute in any calendar year at least the sum of (i) 85% of our ordinary income for such year, (ii) 95% of our capital gain net income for such year and (iii) any undistributed taxable income from the prior year, we would be subject to a non-deductible 4% excise tax on the excess of such required distribution over the sum of (a) the amounts actually distributed and (b) the amounts of income we retained and on which we have paid corporate income tax. Dividends declared by December 31 and paid by January 31 are treated as having been a distribution of our taxable income for the prior tax year.
	We and two of our domestic subsidiaries, American Capital Mortgage Investment TRS, LLC and Residential Credit Solutions, Inc., have made joint elections to treat the subsidiaries as taxable REIT subsidiaries. As such, American Capital Mortgage Investment TRS, LLC and Residential Credit Solutions, Inc. are subject to Federal, state and, if applicable, local income tax.
	We evaluate uncertain income tax positions, if any, in accordance with ASC Topic 740, Income Taxes ("ASC 740"). To the extent we incur interest and/or penalties in connection with our tax obligations, such amounts shall be classified as income tax expense on our consolidated statements of operations
Reclassification, Policy [Policy Text Block]	'
	Reclassifications
	Certain prior period amounts in the consolidated financial statements have been reclassified to conform to the current period presentation.
Comparability of Prior Year Financial Data, Policy [Policy Text Block]	'
	Comparative Period Statement of Cash Flows
	The Company removed non-cash components from two line items within the investing section of the previously reported consolidated statement of cash flows for the year ended December 31, 2012, with the effect of decreasing cash used for "purchases of agency securities" and an offsetting decrease in cash flows from "principal collection of agency securities."  These revisions do not affect the amounts previously reported as net cash provided by or used in operating activities, investing activities or financing activities, or the net change in cash and cash equivalents for any period and have no effect on the consolidated balance sheets or statements of operations or net asset value for any period. While the Company has concluded the revisions are not material to the previously reported financial statements, the Company has elected to revise its previously issued statement of cash flows for the year ended December 31, 2012 in this and future reports.

Agency_Securities_Tables

Agency Securities (Tables)	12 Months Ended
	Dec. 31, 2013
Agency Securities [Abstract]	'
Agency Securities [Table Text Block]	'
	The following tables summarize our investments in agency RMBS as of December 31, 2013 and 2012 (dollars in thousands):
		December 31, 2013
		Fannie Mae				Freddie Mac				Ginnie Mae				Total
	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		)
	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		%
			December 31, 2013
			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
		31-Dec-12
		Fannie Mae				Freddie Mac				Total
	Fixed-rate agency RMBS:
	Par value	$	4,939,592			$	965,074			$	5,904,666
	Unamortized premium	271,729				53,375				325,104
	Amortized cost	5,211,321				1,018,449				6,229,770
	Gross unrealized gains	114,750				23,543				138,293
	Gross unrealized losses	(884		)		(137		)		(1,021		)
	Fixed-rate agency RMBS, at fair value	$	5,325,187			$	1,041,855			$	6,367,042
	Weighted average coupon as of December 31, 2012	3.4		%		3.57		%		3.43		%
	Weighted average yield as of December 31, 2012	2.42		%		2.65		%		2.46		%
	Weighted average yield for the year ended December 31, 2012	2.65		%		2.72		%		2.67		%
Summary Of Agency Securities Estimated Weighted Average Life Classifications Text Block	'
	The following table summarizes our agency RMBS as of December 31, 2013 and 2012 according to their estimated weighted average life classification (dollars in thousands):
		December 31, 2013														December 31, 2012
	Weighted Average Life	Fair				Amortized				Weighted			Weighted Average Coupon			Fair				Amortized				Weighted		Weighted Average Coupon
		Value				Cost				Average						Value				Cost				Average
										Yield														Yield
	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	2,142,111				2,159,311				2.29	%		3.2	%		1,759,226				1,731,178				1.94	%	3.09	%
	Greater than five years and less than or equal to 10 years	3,485,241				3,646,188				2.72	%		3.43	%		4,484,509				4,375,925				2.66	%	3.57	%
	Greater than 10 years	5,241				5,600				2.96	%		3.5	%		123,307				122,667				2.52	%	3.12	%
	Total	$	5,641,682			$	5,820,194			2.56	%		3.35	%		$	6,367,042			$	6,229,770			2.46	%	3.43	%
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 years ended December 31, 2013 and 2012 and for the period from commencement of operations on August 9, 2011 through December 31, 2011 (dollars in thousands):
			For the Year Ended December 31,								For the Period from August 9, 2011 (date operations commenced) through December 31, 2011
			2013				2012
	Proceeds from agency RMBS sold		$	7,817,303			$	4,163,571			$	712,191
	Increase (decrease) in receivable for agency RMBS sold		608,646				(271,849		)		271,849
	Less agency RMBS sold, at cost		(8,596,201		)		(3,818,112		)		(980,603		)
	Net realized gain (loss) on sale of agency RMBS		$	(170,252	)		$	73,610			$	3,437
	Gross realized gains on sale of agency RMBS		$	22,424			$	73,668			$	4,262
	Gross realized losses on sale of agency RMBS		(192,676		)		(58		)		(825		)
	Net realized gain (loss) on sale of agency RMBS		$	(170,252	)		$	73,610			$	3,437
	The following table summarizes our net realized gains and losses from the sale of non-agency RMBS during the years ended December 31, 2013 and 2012 (dollars in thousands):
			For the Year Ended December 31,
			2013				2012
	Proceeds from non-agency RMBS sold		$	197,259			$	32,341
	Less: non-agency RMBS sold, at cost		(180,403		)		(30,561		)
	Net realized gain on sale of non-agency RMBS		$	16,856			$	1,780
	Gross realized gain on sale of non-agency RMBS		$	18,790			$	1,780
	Gross realized loss on sale of non-agency RMBS		(1,934		)		—
	Net realized gain on sale of non-agency RMBS		$	16,856			$	1,780
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 December 31, 2013 and 2012 (dollars in thousands):
		December 31, 2013
	Agency RMBS Pledged (1)	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
	Under Derivative Agreements
	Fair value	—				—				—				—
	Accrued interest on pledged agency RMBS	—				—				—				—
	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 pledged amounts of $583.2 million under repurchase agreements related to agency RMBS sold but not yet settled as of December 31, 2013.
		31-Dec-12
	Agency RMBS Pledged	Fannie Mae				Freddie Mac				Total
	Under Repurchase Agreements
	Fair value	$	5,919,044			$	283,882			$	6,202,926
	Accrued interest on pledged agency RMBS	15,662				774				16,436
	Under Derivative Agreements
	Fair value	68,072				5,995				74,067
	Accrued interest on pledged agency RMBS	183				18				201
	Total Fair Value of Agency RMBS Pledged and Accrued Interest	$	6,002,961			$	290,669			$	6,293,630
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 December 31, 2013 and 2012 (dollars in thousands):
		December 31, 2013												December 31, 2012
	Remaining Maturity	Fair Value				Amortized				Accrued Interest on Pledged Agency RMBS				Fair Value				Amortized				Accrued Interest on Pledged Agency RMBS
						Cost												Cost
	30 days or less	$	2,591,560			$	2,672,502			$	7,182			$	2,318,609			$	2,266,686			$	6,401
	31 - 59 days	1,105,167				1,151,447				3,096				1,968,955				1,924,329				5,145
	60 - 90 days	1,261,354				1,299,749				3,455				1,511,192				1,481,403				3,837
	Greater than 90 days	660,654				673,560				1,714				404,170				396,497				1,053
	Total	$	5,618,735			$	5,797,258			$	15,447			$	6,202,926			$	6,068,915			$	16,436
	The following table summarizes our non-agency RMBS pledged as collateral under repurchase agreements by remaining maturity as of December 31, 2013 and 2012 (dollars in thousands):
		December 31, 2013												December 31, 2012
	Remaining Maturity	Fair Value				Amortized				Accrued Interest on Pledged Non-Agency RMBS				Fair Value				Amortized				Accrued Interest on Pledged Non-Agency RMBS
						Cost												Cost
	30 days or less	$	547,087			$	502,063			$	857			$	315,332			$	291,378			$	741
	31 - 59 days	70,478				68,622				57				141,508				122,103				231
	60 - 90 days	64,873				58,091				55				88,825				79,782				167
	Greater than 90 days	216,738				196,644				242				—				—				—
	Total	$	899,176			$	825,420			$	1,211			$	545,665			$	493,263			$	1,139

NonAgency_Securities_Tables

Non-Agency Securities (Tables)	12 Months Ended
	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]	'
Non-Agency Securities [Table Text Block]	'
	The following tables summarize our non-agency RMBS as of December 31, 2013 and 2012 (dollars in thousands):
	December 31, 2013
			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 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.
	31-Dec-12
			Fair				Gross Unrealized								Amortized Cost				Discount				Par/ Current Face				Weighted Average
	Category		Value				Gains				Losses																Coupon (1)			Yield
	Prime		$	113,351			$	10,338			$	—			$	103,013			$	(33,406	)		$	136,419			3.13	%		7.15	%
	Alt-A		403,522				30,325				(911		)		374,108				(226,224		)		600,332				2.02	%		7.36	%
	Option-ARM		68,861				12,761				—				56,100				(38,617		)		94,717				0.6	%		8.08	%
	Subprime		95,669				12,183				—				83,486				(130,937		)		214,423				0.38	%		7.92	%
	Total		$	681,403			$	65,607			$	(911	)		$	616,707			$	(429,184	)		$	1,045,891			1.7	%		7.47	%
	————————
	-1	Coupon rates are floating, except for $11.3 million and $18.6 million fair value of fixed-rate prime and Alt-A non-agency RMBS, respectively, as of December 31, 2012.
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 December 31, 2013 and 2012 (dollars in thousands):
			December 31, 2013														31-Dec-12
	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		$	203,935			$	194,800			5.59	%		2.19	%		$	90,919			$	85,595			6.43	%		1.53	%
	> 5 to ≤ 7 years		211,013				195,913				6.84	%		2.38	%		266,090				240,472				7.24	%		2	%
	>7 years		596,269				536,418				7.7	%		1.08	%		324,394				290,640				7.96	%		1.55	%
	Total		$	1,011,217			$	927,131			7.07	%		1.46	%		$	681,403			$	616,707			7.47	%		1.7	%
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 years ended December 31, 2013 and 2012 and for the period from commencement of operations on August 9, 2011 through December 31, 2011 (dollars in thousands):
			For the Year Ended December 31,								For the Period from August 9, 2011 (date operations commenced) through December 31, 2011
			2013				2012
	Proceeds from agency RMBS sold		$	7,817,303			$	4,163,571			$	712,191
	Increase (decrease) in receivable for agency RMBS sold		608,646				(271,849		)		271,849
	Less agency RMBS sold, at cost		(8,596,201		)		(3,818,112		)		(980,603		)
	Net realized gain (loss) on sale of agency RMBS		$	(170,252	)		$	73,610			$	3,437
	Gross realized gains on sale of agency RMBS		$	22,424			$	73,668			$	4,262
	Gross realized losses on sale of agency RMBS		(192,676		)		(58		)		(825		)
	Net realized gain (loss) on sale of agency RMBS		$	(170,252	)		$	73,610			$	3,437
	The following table summarizes our net realized gains and losses from the sale of non-agency RMBS during the years ended December 31, 2013 and 2012 (dollars in thousands):
			For the Year Ended December 31,
			2013				2012
	Proceeds from non-agency RMBS sold		$	197,259			$	32,341
	Less: non-agency RMBS sold, at cost		(180,403		)		(30,561		)
	Net realized gain on sale of non-agency RMBS		$	16,856			$	1,780
	Gross realized gain on sale of non-agency RMBS		$	18,790			$	1,780
	Gross realized loss on sale of non-agency RMBS		(1,934		)		—
	Net realized gain on sale of non-agency RMBS		$	16,856			$	1,780
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 December 31, 2013 and 2012 (dollars in thousands):
		December 31, 2013												December 31, 2012
	Remaining Maturity	Fair Value				Amortized				Accrued Interest on Pledged Agency RMBS				Fair Value				Amortized				Accrued Interest on Pledged Agency RMBS
						Cost												Cost
	30 days or less	$	2,591,560			$	2,672,502			$	7,182			$	2,318,609			$	2,266,686			$	6,401
	31 - 59 days	1,105,167				1,151,447				3,096				1,968,955				1,924,329				5,145
	60 - 90 days	1,261,354				1,299,749				3,455				1,511,192				1,481,403				3,837
	Greater than 90 days	660,654				673,560				1,714				404,170				396,497				1,053
	Total	$	5,618,735			$	5,797,258			$	15,447			$	6,202,926			$	6,068,915			$	16,436
	The following table summarizes our non-agency RMBS pledged as collateral under repurchase agreements by remaining maturity as of December 31, 2013 and 2012 (dollars in thousands):
		December 31, 2013												December 31, 2012
	Remaining Maturity	Fair Value				Amortized				Accrued Interest on Pledged Non-Agency RMBS				Fair Value				Amortized				Accrued Interest on Pledged Non-Agency RMBS
						Cost												Cost
	30 days or less	$	547,087			$	502,063			$	857			$	315,332			$	291,378			$	741
	31 - 59 days	70,478				68,622				57				141,508				122,103				231
	60 - 90 days	64,873				58,091				55				88,825				79,782				167
	Greater than 90 days	216,738				196,644				242				—				—				—
	Total	$	899,176			$	825,420			$	1,211			$	545,665			$	493,263			$	1,139

Repurchase_Agreements_Tables

Repurchase Agreements (Tables)	12 Months Ended
	Dec. 31, 2013
Disclosure of Repurchase Agreements [Abstract]	'
Schedule of Debt [Table Text Block]	'
	The following table summarizes our borrowings under repurchase arrangements and weighted average interest rates classified by remaining maturities as of December 31, 2013 and 2012 (dollars in thousands):
		December 31, 2013					December 31, 2012
				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	$	3,047,986	0.6	%	14	$	2,547,674	0.61	%	19
	> 1 to ≤ 2 months	816,960		0.55	%	45	2,035,551		0.56	%	46
	> 2 to ≤ 3 months	1,506,888		0.52	%	77	1,315,109		0.54	%	76
	> 3 to ≤ 6 months	621,124		0.54	%	135	243,877		0.51	%	143
	> 6 to ≤ 9 months	147,729		0.49	%	249	14,317		0.62	%	269
	> 9 to ≤ 12 months	191,991		0.5	%	321	89,263		0.62	%	319
	> 12 months	250,000		0.59	%	853	—		—	%	—
	Total	6,582,678		0.56	%	90	6,245,791		0.57	%	50
	U.S. Treasury repurchase agreements
	Short-term	575,514		0.07	%	2	—		—	%	—
	Total repurchase agreements	$	7,158,192	0.52	%	83	$	6,245,791	0.57	%	50

Derivatives_Tables

Derivatives (Tables)	12 Months Ended
	Dec. 31, 2013
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 December 31, 2013 and 2012 (in thousands):
			December 31,
			2013				2012
	Interest rate swaps		$	51,957			$	519
	Interest rate swaptions		50,009				21,944
	U.S. Treasury futures		3,399				—
	TBA securities		2,856				580
	Derivative assets, at fair value		$	108,221			$	23,043
	Interest rate swaps		$	9,490			$	60,188
	TBA securities		1,837				3,538
	Derivative liabilities, at fair value		$	11,327			$	63,726
Schedule of Derivative Instruments, Gain (Loss) in Statement of Financial Performance [Table Text Block]	'
	The following table summarizes the effect of our outstanding derivatives and other securities on our consolidated statements of operations during the years ended December 31, 2013 and 2012 (in thousands):
			For the Year Ended December 31,
			2013										2012
			Realized Loss on Periodic Settlements of Interest Rate Swaps, net			Realized Gain (Loss) 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 (Loss) on Other Derivatives and Securities, net			Unrealized Gain (Loss) on Other Derivatives and Securities, net			Unrealized Gain and
																						Net Interest Income on Linked Transactions, net
	Interest rate swaps		$	(41,006	)	$	101,297		$	97,769			$	(18,458	)	$	(22,560	)	$	(48,930	)	$	—
	Interest rate swaptions		—			18,558			11,550				—			(1,725		)	(5,207		)	—
	TBA securities		—			(47,063		)	3,933				—			(14,057		)	(1,648		)	—
	U.S. Treasuries		—			(12,952		)	(11,862		)		—			(200		)	—			—
	U.S. Treasury futures		—			6,322			3,399				—			—			—			—
	Short sales of U.S. Treasuries		—			45,434			3,259				—			(8,206		)	(2,884		)	—
	REIT equity investments		—			977			(502		)		—			—			—			—
	Linked Transactions		—			—			—				—			—			—			3,384
	Total		$	(41,006	)	$	112,573		$	107,546			$	(18,458	)	$	(46,748	)	$	(58,669	)	$	3,384
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 years ended December 31, 2013 and 2012 and for the period from commencement of operations on August 9, 2011 through December 31, 2011 (in thousands):
		31-Dec-12				Additions/ Long Positions			Expirations/			31-Dec-13
		Notional							Terminations/ Short Positions			Notional
		Amount										Amount
	Interest rate swaps	$	2,940,000			4,225,000			(3,925,000	)		$	3,240,000
	Interest rate swaptions	$	1,150,000			2,150,000			(1,200,000	)		$	2,100,000
	TBA securities	$	(522,188	)		3,295,280			(3,546,908	)		$	(773,816	)
	U.S. Treasuries	$	—			3,709,500			(3,053,500	)		$	656,000
	U.S. Treasury futures	$	—			650,000			(800,000	)		$	(150,000	)
	Short sales of U.S. Treasuries	$	(425,000	)		4,983,500			(4,581,500	)		$	(23,000	)
		31-Dec-11				Additions/ Long Positions			Expirations/			31-Dec-12
		Notional							Terminations/ Short Positions			Notional
		Amount										Amount
	Interest rate swaps	$	875,000			2,890,000			(825,000	)		$	2,940,000
	Interest rate swaptions	$	50,000			1,325,000			(225,000	)		$	1,150,000
	TBA securities	$	(101,000	)		7,233,405			(7,654,593	)		$	(522,188	)
	U.S. Treasuries	$	—			130,000			(130,000	)		$	—
	Short sales of U.S. Treasuries	$	(50,000	)		3,216,000			(3,591,000	)		$	(425,000	)
	Linked Transactions (1)	$	88,671			10,920			(99,591	)		$	—
		9-Aug-11				Additions/ Long Positions			Expirations/			31-Dec-11
		Notional							Terminations/ Short Positions			Notional
		Amount										Amount
	Interest rate swaps	$	—			875,000			—			$	875,000
	Interest rate swaptions	$	—			50,000			—			$	50,000
	TBA securities	$	—			234,000			(335,000	)		$	(101,000	)
	U.S. Treasuries	$	—			190,000			(190,000	)		$	—
	Short sales of U.S. Treasuries	$	—			540,000			(590,000	)		$	(50,000	)
	Linked Transactions (1)	$	—			90,385			(1,714	)		$	88,671
	————————
	-1	The notional amount of Linked Transactions is represented by the current face amount of the underlying securities.
Schedule Of Interest Rate Swap Agreement By Remaining Maturity [Table Text Block]	'
	As of December 31, 2013 and 2012, we had interest rate swap agreements summarized in the tables below (dollars in thousands).
					December 31,
					2013								2012
	Interest Rate Swaps		Balance Sheet Location		Notional Amount				Fair Value				Notional Amount				Fair Value
	Interest rate swap assets		Derivative assets, at fair value		$	2,275,000			$	51,957			$	50,000			$	519
	Interest rate swap liabilities		Derivative liabilities, at fair value		965,000				(9,490		)		2,890,000				(60,188		)
					$	3,240,000			$	42,467			$	2,940,000			$	(59,669	)
	December 31, 2013
			Notional				Fair Value				Weighted Average
			Amount
	Current Maturity Date for Interest Rate Swaps (1)										Fixed			Receive			Maturity
											Pay Rate			Rate (2)			(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
	December 31, 2012
			Notional				Fair Value				Weighted Average
	Current Maturity Date for Interest Rate Swaps (3)		Amount								Fixed			Receive			Maturity
											Pay Rate			Rate (2)			(Years)
	≤ 3 years		$	550,000			$	(6,639	)		0.81	%		0.31	%		2.3
	> 3 to ≤ 5 years		1,215,000				(24,297		)		1.17	%		0.32	%		4.5
	> 5 to ≤ 7 years		550,000				(16,256		)		1.55	%		0.34	%		6.4
	> 7 years		625,000				(12,477		)		1.89	%		0.34	%		9.5
	Total		$	2,940,000			$	(59,669	)		1.33	%		0.32	%		5.5
	————————
	(1)	Includes swaps with an aggregate notional of $1.2 billion with deferred start dates averaging 1.9 years from December 31, 2013.
	(2)	Weighted average receive rate excludes impact of $1.2 billion of forward starting interest rate swaps.
	(3)	Includes swaps with an aggregate notional of $50.0 million with deferred start dates within four months from December 31, 2012.
Schedule of Interest Rate Swaption Agreements Outstandin [Table Text Block]	'
	The following tables present certain information about our interest rate swaption agreements as of December 31, 2013 and 2012 (dollars in thousands):
	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
	December 31, 2012
			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		$	2,156			$	2			0.2		$	125,000			3.3	%		10
	> 3 to ≤ 12 months		635				3				0.3		50,000				2.68	%		7
	>12 to ≤ 24 months		4,117				1,820				1.5		250,000				2.67	%		6.4
	> 24 months		20,298				20,119				3.2		725,000				3.27	%		8.1
	Total / weighted average		$	27,206			$	21,944			2.4		$	1,150,000			3.12	%		7.9
Schedule of Long and Short Position of Derivative Instruments [Table Text Block]	'
	TBA Securities
	As of December 31, 2013 and 2012, we had contracts to purchase ("long position") and sell ("short position") TBA securities on a forward basis, presented in the following table (in thousands):
			December 31,
			2013								2012
	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		$	210,600			$	158			$	182,600			$	580
	Sale of TBA securities		(463,496		)		2,698				—				—
	Total TBA assets		(252,896		)		2,856				182,600				580
	TBA liabilities
	Purchase of TBA securities		—				—				572,134				(992		)
	Sale of TBA securities		(520,920		)		(1,837		)		(1,276,922		)		(2,546		)
	Total TBA liabilities		(520,920		)		(1,837		)		(704,788		)		(3,538		)
	Total net TBA		$	(773,816	)		$	1,019			$	(522,188	)		$	(2,958	)
	————————
	(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.
Net interest income and unrealized gain (loss) on Linked Transactions [Table Text Block]	'
	The following table presents the composition of unrealized gain (loss) and net interest income on Linked Transactions, net during the years ended December 31, 2013 and 2012 and for the period from commencement of operations on August 9, 2011 through December 31, 2011 (in thousands):
			For the Year Ended December 31,								For the Period from August 9, 2011 (date operations commenced) through December 31, 2011
			2013				2012
	Coupon interest income		$	—			$	302			$	457
	Discount accretion		—				590				553
	Interest expense		—				(183		)		(202		)
	Unrealized gain, net		—				2,675				(1,858		)
	Unrealized gain (loss) and net interest income on Linked Transactions, net		$	—			$	3,384			$	(1,050	)

Offsetting_Assets_and_Liabilit1

Offsetting Assets and Liabilities Offsetting Financial and Derivative Assets (Tables)	12 Months Ended
	Dec. 31, 2013
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
	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	)	$	—
	December 31, 2012
	Interest rate swaps (1)	$	60,188	$	—	$	60,188	$	(13,250	)	$	(46,938	)	$	—
	Repurchase agreements	6,245,791		—		6,245,791		(418,888		)	(5,826,903		)	—
	Total	$	6,305,979	$	—	$	6,305,979	$	(432,138	)	$	(5,873,841	)	$	—
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
	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
	December 31, 2012
	Interest rate swaps and swaptions (1)	$	22,463	$	—	$	22,463	$	(13,250	)	$	—		$	9,213
	Receivable under reverse repurchase agreements	418,888		—		418,888		(418,888		)	—			—
	Total	$	441,351	$	—	$	441,351	$	(432,138	)	$	—		$	9,213

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2013
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 December 31, 2013 and 2012, on the consolidated balance sheets by the valuation hierarchy, as described above (in thousands):
		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
	Mortgage servicing rights	—			—			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 repurchase agreements	22,530			—			—			22,530
	Mortgage servicing liability	—			—			15,608			15,608
	Total	$	22,530		$	11,327		$	15,608		$	49,465
		December 31, 2012
		Level 1			Level 2			Level 3			Total
	Assets
	Agency RMBS	$	—		$	6,367,042		$	—		$	6,367,042
	Non-agency RMBS	—			585,734			95,669			681,403
	Derivative assets	—			23,043			—			23,043
	Total	$	—		$	6,975,819		$	95,669		$	7,071,488
	Liabilities
	Derivative liabilities	$	—		$	63,726		$	—		$	63,726
	Obligation to return securities borrowed under repurchase agreements	421,077			—			—			421,077
	Total	$	421,077		$	63,726		$	—		$	484,803
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]	'
	The following tables present a summary of the changes in fair value for Level 3 assets carried at fair value as of December 31, 2013 and 2012 (in thousands):
		For the Year Ended December 31, 2013
		MSR			Non-Agency RMBS			Total
	Balance as of December 31, 2012	$	—		$	95,669		$	95,669
	Unrealized gain	—			10,073			10,073
	Unrealized loss	(117		)	(6,971		)	(7,088		)
	Total unrealized gain (loss), net	(117		)	3,102			2,985
	Purchases	15,725			60,115			75,840
	Sales of securities	—			(6,293		)	(6,293		)
	Principal repayments on securities	—			(9,010		)	(9,010		)
	Discount accretion	—			5,694			5,694
	Transfer out of Level 3	—			(149,277		)	(149,277		)
	Balance as of December 31, 2013	$	15,608		$	—		$	15,608
	Unrealized loss related to Level 3 assets held as of December 31, 2013	$	(117	)	$	—		$	—
		For the Year Ended December 31, 2012
		Non-Agency RMBS			Linked Transactions			Total
	Balance as of December 31, 2011	$	5,969		$	1,746		$	7,715
	Unrealized gain	13,975			827			14,802
	Unrealized loss	(723		)	—			(723		)
	Total unrealized gain, net	13,252			827			14,079
	Purchases of securities	75,102			—			75,102
	Principal repayments on securities	(9,641		)	(291		)	(9,932		)
	Securities recorded upon de-linking of Linked Transactions	7,893			(7,893		)	—
	Net change in borrowings underlying Linked Transactions	—			5,445			5,445
	Discount accretion	3,094			159			3,253
	Accrued interest on Linked Transactions	—			7			7
	Balance as of December 31, 2012	$	95,669		$	—		$	95,669
	Unrealized gain related to Level 3 assets held as of December 31, 2012	$	13,252		$	827		$	14,079
Fair Value Inputs, Assets, Quantitative Information [Table Text Block]	'
	The following table presents the range of our estimates of loan constant prepayment rates and delinquency rates, together with the discount rate used by a third-party pricing provider in estimating the fair value of our Level 3 MSR with fair values totaling $15.6 million as of December 31, 2013, respectively:
		December 31, 2013
	Unobservable Level 3 Input	Minimum		Weighted	Maximum
				Average
	Constant prepayment rate	6%		15%	35%
	Delinquency rate	—%		8%	29%
	Discount rate	16%		16%	16%

Other_Assets_Tables

Other Assets (Tables)	12 Months Ended
	Dec. 31, 2013
Other Assets [Abstract]	'
Schedule of Other Assets [Table Text Block]	'
	The following table summarizes our other assets as of December 31, 2013 and 2012 (dollars in thousands):
		December 31,
		2013 (1)			2012
	Property and equipment, at cost	$	4,024		$	—
	Accumulated depreciation	(164		)	—
	Net property and equipment	3,860			—
	Servicing advances	33,358			—
	Mortgage servicing rights, at fair value	15,608			—
	Prepaid expenses	6,978			512
	Intangible assets	17,000			—
	Other	4,387			1,180
	Total other assets	$	81,191		$	1,692
Schedule of Servicing Assets at Fair Value [Table Text Block]	'
	The following table summarizes activity related to MSR for the year ended December 31, 2013 (dollars in thousands):
		For the Year Ended December 31, 2013
	Balance at beginning of period	$	—
	Additions	15,725
	Changes in fair value due to
	Changes in fair value assumptions	—
	Other changes in fair value	(117		)
	Balance at end of period	$	15,608
Other Income and Other Expense Disclosure [Text Block]	'
	The following table presents the components of servicing and other operating income and expenses for the year ended December 31, 2013 (dollars in thousands):
		For the Year Ended December 31, 2013
	Servicing fee income	$	2,603
	Ancillary and incentive income	735
	Other income	12
	Servicing and other operating income	$	3,350
	Acquisition related costs	$	3,055
	Employee costs	2,845
	Other servicing costs	1,589
	Servicing and other operating expenses	$	7,489

Other_Liabilities_Tables

Other Liabilities (Tables)	12 Months Ended
	Dec. 31, 2013
Other Liabilities [Abstract]	'
Other Liabilities [Table Text Block]	'
	The following table summarizes our accounts payable and other accrued liabilities as of December 31, 2013 and 2012 (dollars in thousands):
		December 31,
		2013 (2)		2012
	Cash collateral held on derivatives	$	32,463	$	—
	Due to manager	1,885		1,162
	Payable for equity securities purchased	4,581		—
	Accrued interest	4,401		5,009
	Mortgage servicing liability, at fair value (1)	15,608		—
	Excise tax payable	574		1,172
	Other accounts payable and accrued expenses	10,203		273
	Total accounts payable and other accrued liabilities	$	69,715	$	7,616

Stockholders_Equity_Equity_Off

Stockholders' Equity Equity Offerings (Tables)	12 Months Ended
	Dec. 31, 2013
Class of Stock [Line Items]	'
Schedule of Stockholders Equity [Table Text Block]	'
	During the years ended December 31, 2013 and 2012, we issued the following shares of common stock (amounts in thousands except per share amounts):
	Public Offering Date	Price Received Per Share (1)		Number of Shares	Net Proceeds (2)
	Feb-13	$	25.4	23,000	$	583,915
	Total	$	25.4	23,000	$	583,915
	Mar-12	$	21.55	13,600	$	292,780
	May-12	22.74		12,650	287,151
	Total	$	22.09	26,250	$	579,931

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2013
Dividends [Abstract]	'
Schedule of Dividends Payable [Table Text Block]	'
	The following table summarizes dividends declared the years ended December 31, 2013 and 2012 and for the period from commencement of operations on August 9, 2011 through December 31, 2011and their related tax characterization.
				Tax Characterization of Dividends
	Year	Dividends Declared Per Share		Ordinary Income		Long-Term Capital Gains Per Share
				Per Share
	2013	$	3.05	$	3.05	$	—
	2012	$	3.6	$	3.6	$	—
	2011	$	1	$	1	$	—

Quarterly_Results_Tables

Quarterly Results (Tables)	12 Months Ended
	Dec. 31, 2013
Quarterly Results [Abstract]	'
Schedule of Quarterly Financial Information [Table Text Block]	'
	The following is a presentation of the quarterly results of operations for the years ended December 31, 2013 and 2012 (in thousands, except per share data).
		For the Three Months Ended
		31-Dec-13			30-Sep-13			30-Jun-13			31-Mar-13
	Interest income	$	69,694		$	70,511		$	63,927		$	51,567
	Interest expense	(10,656		)	(10,949		)	(9,113		)	(8,036		)
	Net interest income	59,038			59,562			54,814			43,531
	Total other losses, net	(62,310		)	(39,154		)	(102,160		)	(63,702		)
	Total expenses	13,676			6,506			7,007			6,221
	Income (loss) before excise tax	(16,948		)	13,902			(54,353		)	(26,392		)
	Excise tax	302			200			—			177
	Net income (loss)	$	(17,250	)	$	13,702		$	(54,353	)	$	(26,569	)
	Net income (loss) per common share—basic and diluted	$	(0.33	)	$	0.25		$	(0.94	)	$	(0.56	)
	Weighted average number of common shares outstanding—basic and diluted	52,028			54,515			57,982			47,469
	Dividends declared per common share	$	0.65		$	0.7		$	0.8		$	0.9
		For the Three Months Ended
		31-Dec-12			30-Sep-12			30-Jun-12			31-Mar-12
	Interest income	$	49,768		$	44,355		$	34,695		$	16,602
	Interest expense	(8,288		)	(7,329		)	(4,786		)	(1,664		)
	Net interest income	41,480			37,026			29,909			14,938
	Total other gains, net	14,164			114,008			5,985			8,508
	Total expenses	4,514			4,360			3,665			2,117
	Income before excise tax	51,130			146,674			32,229			21,329
	Excise tax	741			432			—			9
	Net income	$	50,389		$	146,242		$	32,229		$	21,320
	Net income per common share—basic and diluted	$	1.4		$	4.03		$	1.15		$	1.82
	Weighted average number of common shares outstanding—basic and diluted	36,105			36,262			28,129			11,724
	Dividends declared per common share	$	0.9		$	0.9		$	0.9		$	0.9

Organization_Organization_Deta

Organization Organization (Details)	12 Months Ended
	Dec. 31, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Required Annual Distribution of Taxable Net Income	90.00%

Agency_Securities_Agency_Secur

Agency Securities Agency Securities (Narrative) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
WeightedAverageLifeofAgencySecurities	'6 years 1 month 0 days	'7 years 0 months 0 days
Weighted Average Expected CPR Over Remaining Life of Agency Portfolio	7.00%	9.00%
Collateralized Agency Securities Sold But Not Settled	$583.20	'
Minimum [Member]	'	'
WeightedAverageLifeofAgencySecurities	'2 years 1 month 15 days	'3 years 5 months

Recovered_Sheet1

Agency Securities Agency securities, at fair value (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Schedule of Agency Securities [Line Items]	'	'
Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value	$5,641,682	$6,367,042
Agency Securities [Member]	'	'
Schedule of Agency Securities [Line Items]	'	'
Agency Securities at Par	5,573,593	5,904,666
Agency Securities Unamortized Premium	246,601	325,104
Agency Securities Amortized Cost	5,820,194	6,229,770
Agency Securities, Gross Unrealized Gains	6,368	138,293
Agency Securities, Gross Unrealized Losses	-184,880	-1,021
Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value	5,641,682	6,367,042
Weighted Average Coupon Rate	3.35%	3.43%
Weighted Average Yield Percentage	2.56%	2.46%
Weighted Average Yield Percentage for Period	2.72%	2.67%
Agency Securities [Member] | Fixed Rate Residential Mortgage [Member]	'	'
Schedule of Agency Securities [Line Items]	'	'
Agency Securities Amortized Cost	5,358,579	'
Agency Securities, Gross Unrealized Gains	3,678	'
Agency Securities, Gross Unrealized Losses	-184,565	'
Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value	5,177,692	'
Agency Securities [Member] | Adjustable Rate Residential Mortgage [Member]	'	'
Schedule of Agency Securities [Line Items]	'	'
Agency Securities Amortized Cost	461,615	'
Agency Securities, Gross Unrealized Gains	2,690	'
Agency Securities, Gross Unrealized Losses	-315	'
Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value	463,990	'
Agency Securities [Member] | Fannie Mae [Member]	'	'
Schedule of Agency Securities [Line Items]	'	'
Agency Securities at Par	4,461,621	4,939,592
Agency Securities Unamortized Premium	195,633	271,729
Agency Securities Amortized Cost	4,657,254	5,211,321
Agency Securities, Gross Unrealized Gains	4,230	114,750
Agency Securities, Gross Unrealized Losses	-150,447	-884
Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value	4,511,037	5,325,187
Weighted Average Coupon Rate	3.33%	3.40%
Weighted Average Yield Percentage	2.53%	2.42%
Weighted Average Yield Percentage for Period	2.69%	2.65%
Agency Securities [Member] | Freddie Mac [Member]	'	'
Schedule of Agency Securities [Line Items]	'	'
Agency Securities at Par	1,079,180	965,074
Agency Securities Unamortized Premium	50,265	53,375
Agency Securities Amortized Cost	1,129,445	1,018,449
Agency Securities, Gross Unrealized Gains	1,570	23,543
Agency Securities, Gross Unrealized Losses	-34,433	-137
Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value	1,096,582	1,041,855
Weighted Average Coupon Rate	3.44%	3.57%
Weighted Average Yield Percentage	2.67%	2.65%
Weighted Average Yield Percentage for Period	2.87%	2.72%
Agency Securities [Member] | Ginnie Mae [Member]	'	'
Schedule of Agency Securities [Line Items]	'	'
Agency Securities at Par	32,792	'
Agency Securities Unamortized Premium	703	'
Agency Securities Amortized Cost	33,495	'
Agency Securities, Gross Unrealized Gains	568	'
Agency Securities, Gross Unrealized Losses	0	'
Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value	$34,063	'
Weighted Average Coupon Rate	3.00%	'
Weighted Average Yield Percentage	2.12%	'
Weighted Average Yield Percentage for Period	2.22%	'

Agency_Securities_Weighted_Ave

Agency Securities Weighted Average Life of Agency Securities (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value	$5,641,682	$6,367,042
WeightedAverageLifeofAgencySecurities	'6 years 1 month 0 days	'7 years 0 months 0 days
Prepayment Rate Of Remaining Life Of Investment Portfolio	7.00%	9.00%
Agency Securities [Member]	'	'
Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value	5,641,682	6,367,042
Agency Securities Amortized Cost	5,820,194	6,229,770
Weighted Average Yield Percentage	2.56%	2.46%
Weighted Average Coupon Rate	3.35%	3.43%
Agency Securities [Member] | Less Than Three Years [Domain]	'	'
Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value	9,089	0
Agency Securities Amortized Cost	9,095	0
Weighted Average Yield Percentage	2.38%	0.00%
Weighted Average Coupon Rate	3.49%	0.00%
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	2,142,111	1,759,226
Agency Securities Amortized Cost	2,159,311	1,731,178
Weighted Average Yield Percentage	2.29%	1.94%
Weighted Average Coupon Rate	3.20%	3.09%
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	3,485,241	4,484,509
Agency Securities Amortized Cost	3,646,188	4,375,925
Weighted Average Yield Percentage	2.72%	2.66%
Weighted Average Coupon Rate	3.43%	3.57%
Agency Securities [Member] | Greater than 10 years [Member]	'	'
Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value	5,241	123,307
Agency Securities Amortized Cost	$5,600	$122,667
Weighted Average Yield Percentage	2.96%	2.52%
Weighted Average Coupon Rate	3.50%	3.12%
Minimum [Member]	'	'
WeightedAverageLifeofAgencySecurities	'2 years 1 month 15 days	'3 years 5 months

Agency_Securities_Realized_Gai

Agency Securities Realized Gains and Losses on Agency Securities (Details) (USD $)	5 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2012
Schedule of Agency Securities [Line Items]	'	'	'
Proceeds from Sale of Agency Securities, Debt	$712,191	$7,817,303	$4,163,571
Increase (Decrease) in Other Receivables	271,849	608,646	-271,849
Cost of Sale of Agency Securities	-980,603	-8,596,201	-3,818,112
Gain (Loss) on Sales of Mortgage Backed Securities (MBS)	3,437	-170,252	73,610
Agency Securities [Member]	'	'	'
Schedule of Agency Securities [Line Items]	'	'	'
Agency Securities, Gross Realized Gains	4,262	22,424	73,668
Agency Securities, Gross Realized Losses	-825	-192,676	-58
Gain (Loss) on Sales of Mortgage Backed Securities (MBS)	$3,437	($170,252)	$73,610

Agency_Securities_Agency_Secur1

Agency Securities Agency Securities Pledged Under Borrowing Agreements (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Total Fair Value Of Agency Securities Pledged And Accrued Interest	$5,634,182,000	$6,293,630,000
Collateralized Agency Securities Sold But Not Settled	583,200,000	'
Fannie Mae [Member]	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Total Fair Value Of Agency Securities Pledged And Accrued Interest	4,504,853,000	6,002,961,000
Freddie Mac [Member]	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Total Fair Value Of Agency Securities Pledged And Accrued Interest	1,095,184,000	290,669,000
Ginnie Mae [Member]	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Total Fair Value Of Agency Securities Pledged And Accrued Interest	34,145,000	'
Repurchase Agreements [Member] | Agency Securities [Member]	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Agency Securities Pledged As Collateral	5,618,735,000	6,202,926,000
Agency Securities Pledged As Collateral Amortized Cost	5,797,258,000	6,068,915,000
Agency Securities Pledged As Collateral Accrued Interest	15,447,000	16,436,000
Repurchase Agreements [Member] | Agency Securities [Member] | Fannie Mae [Member]	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Agency Securities Pledged As Collateral	4,492,566,000	5,919,044,000
Agency Securities Pledged As Collateral Accrued Interest	12,287,000	15,662,000
Repurchase Agreements [Member] | Agency Securities [Member] | Freddie Mac [Member]	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Agency Securities Pledged As Collateral	1,092,106,000	283,882,000
Agency Securities Pledged As Collateral Accrued Interest	3,078,000	774,000
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	'
Agency Securities Pledged As Collateral Accrued Interest	82,000	'
Under Derivative Agreements [Member] | Agency Securities [Member]	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Agency Securities Pledged As Collateral	0	74,067,000
Agency Securities Pledged As Collateral Accrued Interest	0	201,000
Under Derivative Agreements [Member] | Agency Securities [Member] | Fannie Mae [Member]	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Agency Securities Pledged As Collateral	0	68,072,000
Agency Securities Pledged As Collateral Accrued Interest	0	183,000
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	5,995,000
Agency Securities Pledged As Collateral Accrued Interest	0	18,000
Under Derivative Agreements [Member] | Agency Securities [Member] | Ginnie Mae [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_Agency_Secur2

Agency Securities Agency Securities Pledged As Collateral by Maturity Date (Details) (Repurchase Agreements [Member], Agency Securities [Member], USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Security Owned and Pledged as Collateral, Fair Value	$5,618,735	$6,202,926
Agency Securities Pledged As Collateral Amortized Cost	5,797,258	6,068,915
Pledged Assets, Not Separately Reported, Other	15,447	16,436
Maturity up to 30 days [Member]	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Security Owned and Pledged as Collateral, Fair Value	2,591,560	2,318,609
Agency Securities Pledged As Collateral Amortized Cost	2,672,502	2,266,686
Pledged Assets, Not Separately Reported, Other	7,182	6,401
Maturity 31 To 59 Days [Member]	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Security Owned and Pledged as Collateral, Fair Value	1,105,167	1,968,955
Agency Securities Pledged As Collateral Amortized Cost	1,151,447	1,924,329
Pledged Assets, Not Separately Reported, Other	3,096	5,145
Maturity 60 To 90 Days [Member]	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Security Owned and Pledged as Collateral, Fair Value	1,261,354	1,511,192
Agency Securities Pledged As Collateral Amortized Cost	1,299,749	1,481,403
Pledged Assets, Not Separately Reported, Other	3,455	3,837
Maturity over 90 days [Member]	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Security Owned and Pledged as Collateral, Fair Value	660,654	404,170
Agency Securities Pledged As Collateral Amortized Cost	673,560	396,497
Pledged Assets, Not Separately Reported, Other	$1,714	$1,053

NonAgency_Securities_Schedule_

Non-Agency Securities Schedule of Non-Agency Securities (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Narrative [Abstract]	'	'
Non-Agency Securities, at Fair Value	$1,011,217,000	$681,403,000
Prime [Member]	'	'
Non-Agency Security, at Fair Value	195,524,000	113,351,000
Gross Unrealized Gain on Non-Agency Securities	14,161,000	10,338,000
Gross Unrealized Loss on Non-Agency Securities	-5,658,000	0
Non-Agency Securities, at Amortized Cost	187,021,000	103,013,000
Debt Instrument, Unamortized Discount	-222,436,000	-33,406,000
Non-Agency Securities at Par	409,457,000	136,419,000
Weighted Average Coupon Rate	2.00%	3.13%
Weighted Average Yield Percentage	6.13%	7.15%
Narrative [Abstract]	'	'
Fixed Rate Non-Agency Security	67,400,000	11,300,000
Prime [Member] | Interest-Only-Strip [Member]	'	'
Non-Agency Securities at Par	206,400,000	'
Narrative [Abstract]	'	'
Non-Agency Securities, at Fair Value	11,000,000	'
Alt-A [Member]	'	'
Non-Agency Security, at Fair Value	467,531,000	403,522,000
Gross Unrealized Gain on Non-Agency Securities	46,311,000	30,325,000
Gross Unrealized Loss on Non-Agency Securities	-3,420,000	-911,000
Non-Agency Securities, at Amortized Cost	424,640,000	374,108,000
Debt Instrument, Unamortized Discount	-199,407,000	-226,224,000
Non-Agency Securities at Par	624,047,000	600,332,000
Weighted Average Coupon Rate	1.56%	2.02%
Weighted Average Yield Percentage	7.60%	7.36%
Narrative [Abstract]	'	'
Fixed Rate Non-Agency Security	16,600,000	18,600,000
Option-Arm [Member]	'	'
Non-Agency Security, at Fair Value	119,054,000	68,861,000
Gross Unrealized Gain on Non-Agency Securities	14,809,000	12,761,000
Gross Unrealized Loss on Non-Agency Securities	-1,650,000	0
Non-Agency Securities, at Amortized Cost	105,895,000	56,100,000
Debt Instrument, Unamortized Discount	-45,367,000	-38,617,000
Non-Agency Securities at Par	151,262,000	94,717,000
Weighted Average Coupon Rate	0.54%	0.60%
Weighted Average Yield Percentage	7.40%	8.08%
Subprime [Member]	'	'
Non-Agency Security, at Fair Value	229,108,000	95,669,000
Gross Unrealized Gain on Non-Agency Securities	21,471,000	12,183,000
Gross Unrealized Loss on Non-Agency Securities	-1,938,000	0
Non-Agency Securities, at Amortized Cost	209,575,000	83,486,000
Debt Instrument, Unamortized Discount	-132,577,000	-130,937,000
Non-Agency Securities at Par	342,152,000	214,423,000
Weighted Average Coupon Rate	1.01%	0.38%
Weighted Average Yield Percentage	6.69%	7.92%
Narrative [Abstract]	'	'
Fixed Rate Non-Agency Security	51,900,000	'
Non-Agency Securities [Member]	'	'
Non-Agency Security, at Fair Value	1,011,217,000	681,403,000
Gross Unrealized Gain on Non-Agency Securities	96,752,000	65,607,000
Gross Unrealized Loss on Non-Agency Securities	-12,666,000	-911,000
Non-Agency Securities, at Amortized Cost	927,131,000	616,707,000
Debt Instrument, Unamortized Discount	-599,787,000	-429,184,000
Non-Agency Securities at Par	$1,526,918,000	$1,045,891,000
Weighted Average Coupon Rate	1.46%	1.70%
Weighted Average Yield Percentage	7.07%	7.47%
External Credit Rating, Non Investment Grade [Member]	'	'
Percentage of Non-Investment Grade Non-Agency Securities	93.00%	'

NonAgency_Securities_Weighted_

Non-Agency Securities Weighted Average Life of Non-Agency Securities (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Non-Agency Securities, at Fair Value	$1,011,217	$681,403
Less Than or Equal to Five Years [Member]	'	'
Non-Agency Security, at Fair Value	203,935	90,919
Non-Agency Securities, at Amortized Cost	194,800	85,595
Weighted Average Yield Percentage	5.59%	6.43%
Weighted Average Coupon Rate	2.19%	1.53%
Greater Than Five Years and Less Than or Equal to Seven Year [Member]	'	'
Non-Agency Security, at Fair Value	211,013	266,090
Non-Agency Securities, at Amortized Cost	195,913	240,472
Weighted Average Yield Percentage	6.84%	7.24%
Weighted Average Coupon Rate	2.38%	2.00%
Greater Than Seven Years [Member]	'	'
Non-Agency Security, at Fair Value	596,269	324,394
Non-Agency Securities, at Amortized Cost	536,418	290,640
Weighted Average Yield Percentage	7.70%	7.96%
Weighted Average Coupon Rate	1.08%	1.55%
Prime [Member]	'	'
Non-Agency Security, at Fair Value	195,524	113,351
Non-Agency Securities, at Amortized Cost	187,021	103,013
Weighted Average Yield Percentage	6.13%	7.15%
Weighted Average Coupon Rate	2.00%	3.13%
Prime [Member] | Pre-2010 [Member]	'	'
Non-Agency Security, at Fair Value	125,700	'
Prime [Member] | 2013 [Member]	'	'
Non-Agency Security, at Fair Value	69,800	'
Prime [Member] | Minimum [Member]	'	'
Weighted Average Coupon Rate	0.99%	'
Underlying Collateral Coupon	2.39%	'
Prime [Member] | Maximum [Member]	'	'
Weighted Average Coupon Rate	6.50%	'
Underlying Collateral Coupon	6.21%	'
Alt-A [Member]	'	'
Non-Agency Security, at Fair Value	467,531	403,522
Non-Agency Securities, at Amortized Cost	424,640	374,108
Weighted Average Yield Percentage	7.60%	7.36%
Weighted Average Coupon Rate	1.56%	2.02%
Alt-A [Member] | Minimum [Member]	'	'
Weighted Average Coupon Rate	0.23%	'
Underlying Collateral Coupon	2.64%	'
Alt-A [Member] | Maximum [Member]	'	'
Weighted Average Coupon Rate	6.00%	'
Underlying Collateral Coupon	5.97%	'
Option-Arm [Member]	'	'
Non-Agency Security, at Fair Value	119,054	68,861
Non-Agency Securities, at Amortized Cost	105,895	56,100
Weighted Average Yield Percentage	7.40%	8.08%
Weighted Average Coupon Rate	0.54%	0.60%
Option-Arm [Member] | Minimum [Member]	'	'
Weighted Average Coupon Rate	0.34%	'
Underlying Collateral Coupon	2.71%	'
Option-Arm [Member] | Maximum [Member]	'	'
Weighted Average Coupon Rate	1.08%	'
Underlying Collateral Coupon	3.59%	'
Subprime [Member]	'	'
Non-Agency Security, at Fair Value	229,108	95,669
Non-Agency Securities, at Amortized Cost	209,575	83,486
Weighted Average Yield Percentage	6.69%	7.92%
Weighted Average Coupon Rate	1.01%	0.38%
Subprime [Member] | 2013 [Member]	'	'
Non-Agency Security, at Fair Value	33,500	'
Subprime [Member] | Minimum [Member] | 2013 [Member]	'	'
Weighted Average Coupon Rate	3.63%	'
Underlying Collateral Coupon	5.21%	'
Subprime [Member] | Minimum [Member] | Pre-2013 [Member]	'	'
Weighted Average Coupon Rate	0.22%	'
Underlying Collateral Coupon	3.97%	'
Subprime [Member] | Maximum [Member] | 2013 [Member]	'	'
Weighted Average Coupon Rate	4.25%	'
Underlying Collateral Coupon	7.37%	'
Subprime [Member] | Maximum [Member] | Pre-2013 [Member]	'	'
Weighted Average Coupon Rate	4.87%	'
Underlying Collateral Coupon	7.86%	'
Non-Agency Securities [Member]	'	'
Non-Agency Security, at Fair Value	1,011,217	681,403
Non-Agency Securities, at Amortized Cost	$927,131	$616,707
Weighted Average Yield Percentage	7.07%	7.47%
Weighted Average Coupon Rate	1.46%	1.70%

NonAgency_Securities_Realized_

Non-Agency Securities Realized Gains (Losses) from Sale of Non-Agency Securities (Details) (USD $)	5 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2012
Gain (Loss) on Investments [Line Items]	'	'	'
Proceeds from sale of non-agency securities	$0	($197,259)	($32,341)
Realized gain on non-agency securities, net	0	16,856	1,780
Non-Agency Securities [Member]	'	'	'
Gain (Loss) on Investments [Line Items]	'	'	'
Proceeds from sale of non-agency securities	'	197,259	32,341
Cost of Sale of Non-Agency Securities	'	-180,403	-30,561
Available-for-sale Securities, Gross Realized Gains	'	-18,790	-1,780
Available-for-sale Securities, Gross Realized Losses	'	-1,934	0
Realized gain on non-agency securities, net	'	$16,856	$1,780

NonAgency_Securities_NonAgency

Non-Agency Securities Non-Agency Securities Pledged Under Repurchase Agreements (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Short-term Debt [Line Items]	'	'
Non-Agency Securities Pledged Under Repurchase Agreements	$899,200,000	$545,700,000
Non-Agency Securities [Member] | Repurchase Agreements [Member]	'	'
Short-term Debt [Line Items]	'	'
Security Owned and Pledged as Collateral, Fair Value	899,176,000	545,665,000
Agency Securities Pledged As Collateral Amortized Cost	825,420,000	493,263,000
Pledged Assets, Not Separately Reported, Other	1,211,000	1,139,000
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	70,478,000	141,508,000
Agency Securities Pledged As Collateral Amortized Cost	68,622,000	122,103,000
Pledged Assets, Not Separately Reported, Other	57,000	231,000
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	64,873,000	88,825,000
Agency Securities Pledged As Collateral Amortized Cost	58,091,000	79,782,000
Pledged Assets, Not Separately Reported, Other	55,000	167,000
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	216,738,000	0
Agency Securities Pledged As Collateral Amortized Cost	196,644,000	0
Pledged Assets, Not Separately Reported, Other	242,000	0
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	547,087,000	315,332,000
Agency Securities Pledged As Collateral Amortized Cost	502,063,000	291,378,000
Pledged Assets, Not Separately Reported, Other	$857,000	$741,000

Repurchase_Agreements_Schedule

Repurchase Agreements Schedule of Repurchase Agreements (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Statement [Line Items]	'	'
Securities Sold under Agreements to Repurchase	$7,158,192	$6,245,791
Short-term Debt, Weighted Average Interest Rate	0.52%	0.57%
Repurchase Agreements Weighted Average Days To Maturity	8300.00%	5000.00%
Maturity up to 30 days [Member]	'	'
Statement [Line Items]	'	'
Securities Sold under Agreements to Repurchase	3,047,986	2,547,674
Short-term Debt, Weighted Average Interest Rate	0.60%	0.61%
Repurchase Agreements Weighted Average Days To Maturity	1400.00%	1900.00%
Maturity Thirty One To Sixty Days [Member]	'	'
Statement [Line Items]	'	'
Securities Sold under Agreements to Repurchase	816,960	2,035,551
Short-term Debt, Weighted Average Interest Rate	0.55%	0.56%
Repurchase Agreements Weighted Average Days To Maturity	4500.00%	4600.00%
Maturity 61 To 90 Days [Member]	'	'
Statement [Line Items]	'	'
Securities Sold under Agreements to Repurchase	1,506,888	1,315,109
Short-term Debt, Weighted Average Interest Rate	0.52%	0.54%
Repurchase Agreements Weighted Average Days To Maturity	7700.00%	7600.00%
Maturity 90 to 180 Days [Member]	'	'
Statement [Line Items]	'	'
Securities Sold under Agreements to Repurchase	621,124	243,877
Short-term Debt, Weighted Average Interest Rate	0.54%	0.51%
Repurchase Agreements Weighted Average Days To Maturity	13500.00%	14300.00%
Maturity 180 to 270 days [Member]	'	'
Statement [Line Items]	'	'
Securities Sold under Agreements to Repurchase	147,729	14,317
Short-term Debt, Weighted Average Interest Rate	0.49%	0.62%
Repurchase Agreements Weighted Average Days To Maturity	24900.00%	26900.00%
Maturity 271 Days to 365 Days [Member]	'	'
Statement [Line Items]	'	'
Securities Sold under Agreements to Repurchase	191,991	89,263
Short-term Debt, Weighted Average Interest Rate	0.50%	0.62%
Repurchase Agreements Weighted Average Days To Maturity	32100.00%	31900.00%
Greater Than 12 Months [Member]	'	'
Statement [Line Items]	'	'
Securities Sold under Agreements to Repurchase	250,000	0
Short-term Debt, Weighted Average Interest Rate	0.59%	0.00%
Repurchase Agreements Weighted Average Days To Maturity	85300.00%	0.00%
Agency and Non-Agency Securities [Member]	'	'
Statement [Line Items]	'	'
Securities Sold under Agreements to Repurchase	6,582,678	6,245,791
Short-term Debt, Weighted Average Interest Rate	0.56%	0.57%
Repurchase Agreements Weighted Average Days To Maturity	9000.00%	5000.00%
US Treasury Securities [Member]	'	'
Statement [Line Items]	'	'
Securities Sold under Agreements to Repurchase	$575,514	$0
Short-term Debt, Weighted Average Interest Rate	0.07%	0.00%
Repurchase Agreements Weighted Average Days To Maturity	200.00%	0.00%

Repurchase_Agreements_Repurcha

Repurchase Agreements Repurchase Agreements Narrative (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Number of Repo Counterparties	$31	$29
Non-Agency Securities Pledged Under Repurchase Agreements	899,200,000	545,700,000
Collateralized Agency Securities Sold But Not Settled	583,200,000	'
Secured Debt, Repurchase Agreements	7,158,192,000	6,245,791,000
Maximum [Member]	'	'
Risk Of Repurchase Agreement To Stockholders Equity	7.00%	8.00%
Top 5 Repo Counterparties [Member]	'	'
Risk Of Repurchase Agreement To Stockholders Equity	25.00%	26.00%
Agency Securities [Member]	'	'
Secured Debt, Repurchase Agreements	5,900,000,000	'
Repurchase Agreements Weighted Average Days To Maturity	0	'
Non-Agency Securities [Member]	'	'
Secured Debt, Repurchase Agreements	647,100,000	'
Repurchase Agreements Weighted Average Days To Maturity	$0	'

Derivatives_Fair_Value_of_Outs

Derivatives Fair Value of Outstanding Derivatives (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Derivatives, Fair Value [Line Items]	'	'
Derivative assets, at fair value	$108,221	$23,043
Derivative Liabilities	11,327	63,726
Interest Rate Swap Assets [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative assets, at fair value	51,957	519
Derivative Liabilities	9,490	60,188
Payer Swaption [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative assets, at fair value	50,009	21,944
Treasury Futures Asset [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative assets, at fair value	3,399	0
Purchases Of TBAs And Forward Settling Agency Securities [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative assets, at fair value	2,856	580
Derivative Liabilities	$1,837	$3,538

Derivatives_Effect_of_Derivati

Derivatives Effect of Derivatives on Net Income (Details) (USD $)	5 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2012
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'
Realized gain (loss) on periodic interest settlements of interest rate swaps, net	($1,743)	($41,006)	($18,458)
Other realized gain loss on derivative instruments and other securities, net	-3,856	112,573	-46,748
Unrealized Gain Loss On Derivative Instrument And Trading Securities	-2,405	107,546	-58,669
Unrealized gain loss and net interest income on linked transactions, net	-1,050	0	3,384
Interest Rate Swap [Member]	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'
Realized gain (loss) on periodic interest settlements of interest rate swaps, net	'	-41,006	-18,458
Other realized gain loss on derivative instruments and other securities, net	'	101,297	-22,560
Unrealized Gain Loss On Derivative Instrument And Trading Securities	'	97,769	-48,930
Unrealized gain loss and net interest income on linked transactions, net	'	'	0
Interest Rate Swaption [Member]	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'
Realized gain (loss) on periodic interest settlements of interest rate swaps, net	'	0	0
Other realized gain loss on derivative instruments and other securities, net	'	18,558	-1,725
Unrealized Gain Loss On Derivative Instrument And Trading Securities	'	11,550	-5,207
Unrealized gain loss and net interest income on linked transactions, net	'	'	0
Forward Contracts [Member]	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'
Realized gain (loss) on periodic interest settlements of interest rate swaps, net	'	0	0
Other realized gain loss on derivative instruments and other securities, net	'	-47,063	-14,057
Unrealized Gain Loss On Derivative Instrument And Trading Securities	'	3,933	-1,648
Unrealized gain loss and net interest income on linked transactions, net	'	'	0
US Treasury Securities [Member]	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'
Realized gain (loss) on periodic interest settlements of interest rate swaps, net	'	0	0
Other realized gain loss on derivative instruments and other securities, net	'	-12,952	-200
Unrealized Gain Loss On Derivative Instrument And Trading Securities	'	-11,862	0
Unrealized gain loss and net interest income on linked transactions, net	'	'	0
Treasury Futures Short [Member]	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'
Realized gain (loss) on periodic interest settlements of interest rate swaps, net	'	0	0
Other realized gain loss on derivative instruments and other securities, net	'	6,322	0
Unrealized Gain Loss On Derivative Instrument And Trading Securities	'	3,399	0
Unrealized gain loss and net interest income on linked transactions, net	'	'	0
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
Other realized gain loss on derivative instruments and other securities, net	'	45,434	-8,206
Unrealized Gain Loss On Derivative Instrument And Trading Securities	'	3,259	-2,884
Unrealized gain loss and net interest income on linked transactions, net	'	'	0
Equity Securities [Member]	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'
Realized gain (loss) on periodic interest settlements of interest rate swaps, net	'	0	0
Other realized gain loss on derivative instruments and other securities, net	'	977	0
Unrealized Gain Loss On Derivative Instrument And Trading Securities	'	'	0
Unrealized gain loss and net interest income on linked transactions, net	'	'	0
Linked Transactions [Member]	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'
Realized gain (loss) on periodic interest settlements of interest rate swaps, net	'	0	0
Other realized gain loss on derivative instruments and other securities, net	'	0	0
Unrealized Gain Loss On Derivative Instrument And Trading Securities	'	0	0
Unrealized gain loss and net interest income on linked transactions, net	($1,050)	$0	$3,384

Derivatives_Change_in_Derivati

Derivatives Change in Derivative Notional Amounts (Details) (USD $)	5 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013
Derivative [Line Items]	'	'	'	'
Notional Amount of Derivatives	'	'	'	$1,200,000
Interest Rate Swap [Member]	'	'	'	'
Derivative [Line Items]	'	'	'	'
Notional Amount of Derivatives	0	2,940,000	875,000	3,240,000
Notional Amount Of Derivatives Not Designated As Hedging Instruments Additions During The Period	875,000	4,225,000	2,890,000	'
Notional Amount Of Derivatives Not Designated As Hedging Instruments Settlement Expiration During The Period	0	-3,925,000	-825,000	'
Interest Rate Swaption [Member]	'	'	'	'
Derivative [Line Items]	'	'	'	'
Notional Amount of Derivatives	0	1,150,000	50,000	2,100,000
Notional Amount Of Derivatives Not Designated As Hedging Instruments Additions During The Period	50,000	2,150,000	1,325,000	'
Notional Amount Of Derivatives Not Designated As Hedging Instruments Settlement Expiration During The Period	0	-1,200,000	-225,000	'
Forward Contracts [Member]	'	'	'	'
Derivative [Line Items]	'	'	'	'
Notional Amount of Derivatives	0	-522,188	-101,000	-773,816
Notional Amount Of Derivatives Not Designated As Hedging Instruments Additions During The Period	234,000	3,295,280	7,233,405	'
Notional Amount Of Derivatives Not Designated As Hedging Instruments Settlement Expiration During The Period	-335,000	-3,546,908	-7,654,593	'
US Treasury Securities [Member]	'	'	'	'
Derivative [Line Items]	'	'	'	'
Notional Amount of Derivatives	0	0	0	656,000
Notional Amount Of Derivatives Not Designated As Hedging Instruments Additions During The Period	190,000	3,709,500	130,000	'
Notional Amount Of Derivatives Not Designated As Hedging Instruments Settlement Expiration During The Period	-190,000	-3,053,500	-130,000	'
Treasury Futures Short [Member]	'	'	'	'
Derivative [Line Items]	'	'	'	'
Notional Amount of Derivatives	'	0	'	-150,000
Notional Amount Of Derivatives Not Designated As Hedging Instruments Additions During The Period	'	650,000	'	'
Notional Amount Of Derivatives Not Designated As Hedging Instruments Settlement Expiration During The Period	'	-800,000	'	'
Linked Transactions [Member]	'	'	'	'
Derivative [Line Items]	'	'	'	'
Notional Amount of Derivatives	0	'	88,671	'
Notional Amount Of Derivatives Not Designated As Hedging Instruments Additions During The Period	90,385	'	10,920	'
Notional Amount Of Derivatives Not Designated As Hedging Instruments Settlement Expiration During The Period	-1,714	'	-99,591	'
Short Sales Of U S Government Securities [Member]	'	'	'	'
Derivative [Line Items]	'	'	'	'
Notional Amount of Derivatives	0	-425,000	-50,000	-23,000
Notional Amount Of Derivatives Not Designated As Hedging Instruments Additions During The Period	540,000	4,983,500	3,216,000	'
Notional Amount Of Derivatives Not Designated As Hedging Instruments Settlement Expiration During The Period	($590,000)	($4,581,500)	($3,591,000)	'

Derivatives_Interest_Rate_Swap

Derivatives Interest Rate Swap Agreements (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Derivative [Line Items]	'	'
Notional Amount of Derivatives	$1,200,000	$50,000
Interest Rate Swap [Member]	'	'
Derivative [Line Items]	'	'
Interest Rate Derivatives, at Fair Value, Net	42,467	-59,669
Notional Amount of Derivatives	3,240,000	2,940,000
Weighted Average Effective Date	'1 year 11 months	'
Interest Rate Derivative Instruments Not Designated as Hedging Instruments at Fair Value, Net	42,467	-59,669
Interest Rate Derivative Not Designated As Hedging Instruments Average Fixed Pay Rate	1.90%	1.33%
Interest Rate Derivative Not Designated As Hedging Instruments Average receive Rate	0.24%	0.32%
Derivative, Average Remaining Maturity	'5 years 5 months	'5 years 5 months 27 days
Assets [Member] | Interest Rate Swap [Member]	'	'
Derivative [Line Items]	'	'
Interest Rate Derivatives, at Fair Value, Net	51,957	519
Notional Amount of Derivatives	2,275,000	50,000
Liability [Member] | Interest Rate Swap [Member]	'	'
Derivative [Line Items]	'	'
Interest Rate Derivatives, at Fair Value, Net	-9,490	-60,188
Notional Amount of Derivatives	965,000	2,890,000
Greater Than One Year and Less Than or Equal to Three Years [Member] | Interest Rate Swap [Member]	'	'
Derivative [Line Items]	'	'
Notional Amount of Derivatives	650,000	550,000
Interest Rate Derivative Instruments Not Designated as Hedging Instruments at Fair Value, Net	-6,612	-6,639
Interest Rate Derivative Not Designated As Hedging Instruments Average Fixed Pay Rate	0.87%	0.81%
Interest Rate Derivative Not Designated As Hedging Instruments Average receive Rate	0.24%	0.31%
Derivative, Average Remaining Maturity	'1 year 5 months	'2 years 3 months 11 days
Greater Than Three Years and Less Than or Equal to Five Years [Member] | Interest Rate Swap [Member]	'	'
Derivative [Line Items]	'	'
Notional Amount of Derivatives	815,000	1,215,000
Interest Rate Derivative Instruments Not Designated as Hedging Instruments at Fair Value, Net	4,722	-24,297
Interest Rate Derivative Not Designated As Hedging Instruments Average Fixed Pay Rate	1.11%	1.17%
Interest Rate Derivative Not Designated As Hedging Instruments Average receive Rate	0.24%	0.32%
Derivative, Average Remaining Maturity	'3 years 11 months	'4 years 5 months 16 days
Greater Than Five Years and Less than or Equal to Seven Years [Member] | Interest Rate Swap [Member]	'	'
Derivative [Line Items]	'	'
Notional Amount of Derivatives	1,025,000	550,000
Interest Rate Derivative Instruments Not Designated as Hedging Instruments at Fair Value, Net	21,434	-16,256
Interest Rate Derivative Not Designated As Hedging Instruments Average Fixed Pay Rate	2.28%	1.55%
Interest Rate Derivative Not Designated As Hedging Instruments Average receive Rate	0.24%	0.34%
Derivative, Average Remaining Maturity	'6 years 5 months	'6 years 4 months 28 days
Greater Than Seven Years and Less than or Equal to Ten Years [Member] | Interest Rate Swap [Member]	'	'
Derivative [Line Items]	'	'
Notional Amount of Derivatives	750,000	625,000
Interest Rate Derivative Instruments Not Designated as Hedging Instruments at Fair Value, Net	22,923	-12,477
Interest Rate Derivative Not Designated As Hedging Instruments Average Fixed Pay Rate	3.12%	1.89%
Interest Rate Derivative Not Designated As Hedging Instruments Average receive Rate	0.24%	0.34%
Derivative, Average Remaining Maturity	'9 years 1 month	'9 years 6 months 4 days
Exchange Cleared [Member] | Assets [Member] | Interest Rate Swap [Member]	'	'
Derivative [Line Items]	'	'
Interest Rate Derivatives, at Fair Value, Net	21,400	'
Notional Amount of Derivatives	$1,300,000	'
Maximum [Member]	'	'
Derivative [Line Items]	'	'
Percent of Equity at Risk Under Derivative Assets	2.00%	1.00%

Derivatives_Interest_Rate_Swap1

Derivatives Interest Rate Swap by Remaining Maturity (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Derivative [Line Items]	'	'
Notional Amount of Derivatives	$1,200,000	$50,000
Interest Rate Swap [Member]	'	'
Derivative [Line Items]	'	'
Derivative, Variable Interest Rate	0.24%	0.32%
Notional Amount of Derivatives	3,240,000	2,940,000
Weighted Average Effective Date	'1 year 11 months	'
Interest Rate Derivative Instruments Not Designated as Hedging Instruments at Fair Value, Net	42,467	-59,669
Derivative, Average Fixed Interest Rate	1.90%	1.33%
Derivative, Average Remaining Maturity	'5 years 5 months	'5 years 5 months 27 days
Interest Rate Swap [Member] | Greater Than One Year and Less Than or Equal to Three Years [Member]	'	'
Derivative [Line Items]	'	'
Derivative, Variable Interest Rate	0.24%	0.31%
Notional Amount of Derivatives	650,000	550,000
Interest Rate Derivative Instruments Not Designated as Hedging Instruments at Fair Value, Net	-6,612	-6,639
Derivative, Average Fixed Interest Rate	0.87%	0.81%
Derivative, Average Remaining Maturity	'1 year 5 months	'2 years 3 months 11 days
Interest Rate Swap [Member] | Greater Than Three Years and Less Than or Equal to Five Years [Member]	'	'
Derivative [Line Items]	'	'
Derivative, Variable Interest Rate	0.24%	0.32%
Notional Amount of Derivatives	815,000	1,215,000
Interest Rate Derivative Instruments Not Designated as Hedging Instruments at Fair Value, Net	4,722	-24,297
Derivative, Average Fixed Interest Rate	1.11%	1.17%
Derivative, Average Remaining Maturity	'3 years 11 months	'4 years 5 months 16 days
Interest Rate Swap [Member] | Greater Than Five Years and Less than or Equal to Seven Years [Member]	'	'
Derivative [Line Items]	'	'
Derivative, Variable Interest Rate	0.24%	0.34%
Notional Amount of Derivatives	1,025,000	550,000
Interest Rate Derivative Instruments Not Designated as Hedging Instruments at Fair Value, Net	21,434	-16,256
Derivative, Average Fixed Interest Rate	2.28%	1.55%
Derivative, Average Remaining Maturity	'6 years 5 months	'6 years 4 months 28 days
Interest Rate Swap [Member] | Greater Than Seven Years and Less than or Equal to Ten Years [Member]	'	'
Derivative [Line Items]	'	'
Derivative, Variable Interest Rate	0.24%	0.34%
Notional Amount of Derivatives	750,000	625,000
Interest Rate Derivative Instruments Not Designated as Hedging Instruments at Fair Value, Net	$22,923	($12,477)
Derivative, Average Fixed Interest Rate	3.12%	1.89%
Derivative, Average Remaining Maturity	'9 years 1 month	'9 years 6 months 4 days

Derivatives_Interest_Rate_Swap2

Derivatives Interest Rate Swaptions (Details) (USD $)

12 Months Ended

12 Months Ended

12 Months Ended

12 Months Ended

12 Months Ended

12 Months Ended

In Thousands, unless otherwise specified

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Aug. 09, 2011

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Interest Rate Swaption [Member]

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

$27,206

'

'

'

'

'

$2,156

$635

$4,117

$20,298

$43,722

'

$17,015

'

$13,868

'

$8,105

'

$4,734

'

Interest Rate Derivatives, at Fair Value, Net

'

'

'

'

'

'

'

'

'

'

50,009

21,944

19,841

2

10,406

3

8,979

1,820

10,783

20,119

Weighted Average Years to Swaption Maturity

'2 years 5 months 0 days

'

'

'

'

'

'0 years 2 months 8 days

'0 years 3 months 2 days

'1 year 6 months

'3 years 2 months

'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

'

Notional Amount of Interest Rate Derivatives

$50,000

$1,200,000

$2,100,000

$1,150,000

$50,000

$0

'

'

'

'

$2,100,000

$1,150,000

$925,000

$125,000

$550,000

$50,000

$400,000

$250,000

$225,000

$725,000

Interest Rate Derivative Not Designated As Hedging instruments Pay Rate

3.12%

'

'

'

'

'

3.30%

2.68%

2.67%

3.27%

2.99%

'

2.59%

'

2.94%

'

3.63%

'

3.62%

'

Derivatives Average Term

'7 years 11 months 0 days

'

'

'

'

'

'10 years 0 months 0 days

'7 years 0 months 0 days

'6 years 5 months

'8 years 1 month

'7 years 6 months

'

'8 years 0 months

'

'8 years 2 months

'

'6 years 4 months

'

'5 years 11 months

'

Derivatives_TBA_Securities_Det

Derivatives TBA Securities (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Derivative [Line Items]	'	'
Notional Amount of Derivatives	$1,200,000	$50,000
TBA securities Fifteen Year and Thirty Year Securities [Member]	'	'
Derivative [Line Items]	'	'
Notional Amount of Derivatives	-773,816	-522,188
Derivative, Fair Value, Net	1,019	-2,958
TBA securities Fifteen Year and Thirty Year Securities [Member] | Derivative liabilities [Member]	'	'
Derivative [Line Items]	'	'
Notional Amount of Derivatives	-520,920	-704,788
Derivative, Fair Value, Net	-1,837	-3,538
TBA securities Fifteen Year and Thirty Year Securities [Member] | Derivative liabilities [Member] | Short Position [Member]	'	'
Derivative [Line Items]	'	'
Notional Amount of Derivatives	-520,920	-1,276,922
Derivative, Fair Value, Net	-1,837	-2,546
TBA securities Fifteen Year and Thirty Year Securities [Member] | Derivative liabilities [Member] | Long Position [Member]	'	'
Derivative [Line Items]	'	'
Notional Amount of Derivatives	0	572,134
Derivative, Fair Value, Net	0	-992
TBA securities Fifteen Year and Thirty Year Securities [Member] | Derivative Assets [Member]	'	'
Derivative [Line Items]	'	'
Notional Amount of Derivatives	-252,896	182,600
Derivative, Fair Value, Net	2,856	580
TBA securities Fifteen Year and Thirty Year Securities [Member] | Derivative Assets [Member] | Short Position [Member]	'	'
Derivative [Line Items]	'	'
Notional Amount of Derivatives	-463,496	0
Derivative, Fair Value, Net	2,698	0
TBA securities Fifteen Year and Thirty Year Securities [Member] | Derivative Assets [Member] | Long Position [Member]	'	'
Derivative [Line Items]	'	'
Notional Amount of Derivatives	210,600	182,600
Derivative, Fair Value, Net	$158	$580

Derivatives_Linked_Transaction

Derivatives Linked Transactions (Details) (USD $)	3 Months Ended								5 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2012
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Investment Income, Interest	$69,694	$70,511	$63,927	$51,567	$49,768	$44,355	$34,695	$16,602	'	'	'
Accretion of Discount	'	'	'	'	'	'	'	'	-799	-35,496	-14,209
Unrealized gain loss and net interest income on linked transactions, net	'	'	'	'	'	'	'	'	-1,050	0	3,384
Linked Transactions [Member]	'	'	'	'	'	'	'	'	'	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Investment Income, Interest	'	'	'	'	'	'	'	'	457	0	302
Accretion of Discount	'	'	'	'	'	'	'	'	553	0	590
Interest Expense, Securities Sold under Agreements to Repurchase	'	'	'	'	'	'	'	'	-202	0	-183
Unrealized Gain (Loss) on Securities	'	'	'	'	'	'	'	'	-1,858	0	2,675
Unrealized gain loss and net interest income on linked transactions, net	'	'	'	'	'	'	'	'	($1,050)	$0	$3,384

Derivatives_REIT_Equity_Securi

Derivatives REIT Equity Securities (Details) (USD $)	5 Months Ended	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]	'	'	'
Marketable Securities, Equity Securities	'	$38,807,000	$0
Unrealized Gain Loss On Derivative Instrument And Trading Securities	-2,405,000	107,546,000	-58,669,000
Other realized gain loss on derivative instruments and other securities, net	-3,856,000	112,573,000	-46,748,000
Equity Securities [Member]	'	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'	'
Investment Owned, at Cost	'	39,300,000	'
Unrealized Gain Loss On Derivative Instrument And Trading Securities	'	-502,000	'
Equity Securities [Member]	'	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'	'
Unrealized Gain Loss On Derivative Instrument And Trading Securities	'	'	0
Other realized gain loss on derivative instruments and other securities, net	'	$977,000	$0

Derivatives_US_Treasury_Securi

Derivatives U.S. Treasury Securities and Futures (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Aug. 09, 2011
In Thousands, unless otherwise specified
Open Option Contracts Written [Line Items]	'	'	'	'
US Government Securities, at Carrying Value	$637,342	$0	'	'
Notional Amount of Derivatives	1,200,000	50,000	'	'
Derivative Liabilities	11,327	63,726	'	'
Obligation to Return Securities Borrowed Under Reverse Repurchase Agreements at Fair Value	22,530	421,077	'	'
Receivable Under Reverse Repurchase Agreements	22,736	418,888	'	'
US Treasury Securities [Member]	'	'	'	'
Open Option Contracts Written [Line Items]	'	'	'	'
Notional Amount of Derivatives	656,000	0	0	0
Treasury Futures Short [Member]	'	'	'	'
Open Option Contracts Written [Line Items]	'	'	'	'
Notional Amount of Derivatives	-150,000	0	'	'
Derivative Liabilities	$3,400	'	'	'

Offsetting_Assets_and_Liabilit2

Offsetting Assets and Liabilities Offsetting of Financial Assets and Liabilities (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Derivative Assets [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Gross Amount of Recognized Assets (Liabilities)	$101,966	$22,463
Gross Amounts Offset on the Balance Sheet	0	0
Net Amount of Assets (Liabilities) Presented on the Balance Sheet	101,966	22,463
Gross Amounts of Financial Instruments Not Offset on the Balance Sheet	-9,490	-13,250
Gross Amounts of Cash Collateral Not Offset on the Balance Sheet	-45,084	0
Net Amount After Deducting Gross Amounts Not Offset on the Balance Sheet From Net Amount of Assets (Liabilities) Presented on the Balance Sheet	47,392	9,213
Derivative Assets [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Gross Amount of Recognized Assets (Liabilities)	7,167,682	6,305,979
Gross Amounts Offset on the Balance Sheet	0	0
Net Amount of Assets (Liabilities) Presented on the Balance Sheet	7,167,682	6,305,979
Gross Amounts of Financial Instruments Not Offset on the Balance Sheet	-32,226	-432,138
Gross Amounts of Cash Collateral Not Offset on the Balance Sheet	-7,135,456	-5,873,841
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)	22,736	418,888
Gross Amounts Offset on the Balance Sheet	0	0
Net Amount of Assets (Liabilities) Presented on the Balance Sheet	22,736	418,888
Gross Amounts of Financial Instruments Not Offset on the Balance Sheet	-22,736	-418,888
Gross Amounts of Cash Collateral Not Offset on the Balance Sheet	0	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
Assets [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Gross Amount of Recognized Assets (Liabilities)	124,702	441,351
Gross Amounts Offset on the Balance Sheet	0	0
Net Amount of Assets (Liabilities) Presented on the Balance Sheet	124,702	441,351
Gross Amounts of Financial Instruments Not Offset on the Balance Sheet	-32,226	-432,138
Gross Amounts of Cash Collateral Not Offset on the Balance Sheet	-45,084	0
Net Amount After Deducting Gross Amounts Not Offset on the Balance Sheet From Net Amount of Assets (Liabilities) Presented on the Balance Sheet	47,392	9,213
Derivative liabilities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Gross Amount of Recognized Assets (Liabilities)	9,490	60,188
Gross Amounts Offset on the Balance Sheet	0	0
Net Amount of Assets (Liabilities) Presented on the Balance Sheet	9,490	60,188
Gross Amounts of Financial Instruments Not Offset on the Balance Sheet	-9,490	-13,250
Gross Amounts of Cash Collateral Not Offset on the Balance Sheet	0	-46,938
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	6,245,791
Gross Amounts Offset on the Balance Sheet	0	0
Net Amount of Assets (Liabilities) Presented on the Balance Sheet	7,158,192	6,245,791
Gross Amounts of Financial Instruments Not Offset on the Balance Sheet	-22,736	-418,888
Gross Amounts of Cash Collateral Not Offset on the Balance Sheet	-7,135,456	-5,826,903
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

Fair_Value_Measurements_Financ

Fair Value Measurements Financial Instruments Measured on a Recurring Basis (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value	$5,641,682	$6,367,042
US Government Securities, at Carrying Value	637,342	0
Derivative Asset	108,221	23,043
Servicing Asset at Fair Value, Amount	15,608	0
Derivative liabilities, at fair value	11,327	63,726
Obligation to Return Securities Borrowed Under Reverse Repurchase Agreements at Fair Value	22,530	421,077
Servicing Liability	15,608	0
Fair Value, Measurements, Recurring [Member]	'	'
Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value	5,641,682	6,367,042
Non-Agency Security, at Fair Value	1,011,217	681,403
Marketable Securities	38,807	'
Financial Instruments, Owned, US Government and Agency Obligations, at Fair Value	637,342	'
Derivative Asset	108,221	23,043
Servicing Asset at Fair Value, Amount	15,608	'
Assets, Fair Value Disclosure, Recurring	7,452,877	7,071,488
Derivative liabilities, at fair value	11,327	63,726
Obligation to Return Securities Borrowed Under Reverse Repurchase Agreements at Fair Value	22,530	421,077
Servicing Liability	15,608	'
Liabilities, Fair Value Disclosure, Recurring	49,465	484,803
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	637,342	'
Derivative Asset	0	0
Servicing Asset at Fair Value, Amount	0	'
Assets, Fair Value Disclosure, Recurring	676,149	0
Derivative liabilities, at fair value	0	0
Obligation to Return Securities Borrowed Under Reverse Repurchase Agreements at Fair Value	22,530	421,077
Servicing Liability	0	'
Liabilities, Fair Value Disclosure, Recurring	22,530	421,077
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]	'	'
Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value	5,641,682	6,367,042
Non-Agency Security, at Fair Value	1,011,217	585,734
Marketable Securities	0	'
Financial Instruments, Owned, US Government and Agency Obligations, at Fair Value	0	'
Derivative Asset	108,221	23,043
Servicing Asset at Fair Value, Amount	0	'
Assets, Fair Value Disclosure, Recurring	6,761,120	6,975,819
Derivative liabilities, at fair value	11,327	63,726
Obligation to Return Securities Borrowed Under Reverse Repurchase Agreements at Fair Value	0	0
Servicing Liability	0	'
Liabilities, Fair Value Disclosure, Recurring	11,327	63,726
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	15,608	'
Financial Instruments, Owned, Mortgages, Mortgage-backed and Asset-backed Securities, at Fair Value	0	0
Non-Agency Security, at Fair Value	'	95,669
Marketable Securities	0	'
Financial Instruments, Owned, US Government and Agency Obligations, at Fair Value	0	'
Derivative Asset	0	0
Servicing Asset at Fair Value, Amount	15,608	'
Assets, Fair Value Disclosure, Recurring	15,608	95,669
Derivative liabilities, at fair value	0	0
Obligation to Return Securities Borrowed Under Reverse Repurchase Agreements at Fair Value	0	0
Servicing Liability	15,608	'
Liabilities, Fair Value Disclosure, Recurring	$15,608	$0

Fair_Value_Measurements_Level_

Fair Value Measurements Level 3 Financial Assets and Liabilities (Details) (USD $)	5 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2012
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'	'	'
Interest Receivable	'	$20,620	$18,265
Unrealized Gain (Loss) on Investments	-433	19,391	64,310
Fair Value, Inputs, Level 3 [Member]	'	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	7,715	'	95,669
Unrealized Gain on Securities	'	10,073	14,802
Unrealized Loss on Securities	'	7,088	723
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	'	2,985	14,079
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	'	75,840	75,102
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	'	-6,293	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	'	-9,010	-9,932
Accretion (Amortization) of Discounts and Premiums, Investments	'	5,694	3,253
Interest Receivable	'	'	7
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	'	-149,277	'
Securities Recorded Upon De-linking of Linked Transactions	'	'	0
Repayments of Other Debt	'	'	5,445
Unrealized Gain (Loss) on Investments	'	0	'
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]	'	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'	'	'
Servicing Asset	'	15,608	'
Fair Value, Inputs, Level 3 [Member] | Servicing Contracts [Member]	'	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	'	15,608	0
Unrealized Gain on Securities	'	0	'
Unrealized Loss on Securities	'	117	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	'	-117	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	'	15,725	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	'	0	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	'	0	'
Accretion (Amortization) of Discounts and Premiums, Investments	'	0	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	'	0	'
Unrealized Gain (Loss) on Investments	'	-117	'
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	5,969	0	95,669
Unrealized Gain on Securities	'	10,073	13,975
Unrealized Loss on Securities	'	6,971	723
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	'	3,102	13,252
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	'	60,115	75,102
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	'	-6,293	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	'	-9,010	-9,641
Accretion (Amortization) of Discounts and Premiums, Investments	'	5,694	3,094
Interest Receivable	'	'	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	'	-149,277	'
Securities Recorded Upon De-linking of Linked Transactions	'	'	7,893
Repayments of Other Debt	'	'	0
Fair Value, Inputs, Level 3 [Member] | Linked Transactions [Member]	'	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	1,746	'	0
Unrealized Gain on Securities	'	'	827
Unrealized Loss on Securities	'	'	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	'	'	827
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	'	'	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	'	'	-291
Accretion (Amortization) of Discounts and Premiums, Investments	'	'	159
Interest Receivable	'	'	7
Securities Recorded Upon De-linking of Linked Transactions	'	'	-7,893
Repayments of Other Debt	'	'	5,445
Subprime [Member]	'	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	'	$149,300	'

Fair_Value_Measurements_Level_1

Fair Value Measurements Level 3 Unobservable Inputs (Details) (USD $)	Dec. 31, 2013
In Thousands, unless otherwise specified
Maximum [Member]	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'
Constant Prepayment Speed	35.00%
Loss Severity	29.00%
Discount Rate	16.00%
Minimum [Member]	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'
Constant Prepayment Speed	6.00%
Loss Severity	0.00%
Discount Rate	16.00%
Weighted Average [Member]	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'
Constant Prepayment Speed	15.00%
Loss Severity	8.00%
Discount Rate	16.00%
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'
Servicing Asset	15,608

Other_Assets_Schedule_of_Other

Other Assets Schedule of Other Assets (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Schedule of Other Assets [Line Items]	'	'
Property, Plant and Equipment, Gross	$4,024	$0
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	164	0
Property, Plant and Equipment, Net	3,860	0
Servicing advances	33,358	0
Servicing Asset at Fair Value, Amount	15,608	0
Prepaid Expense, Current	6,978	512
Goodwill	17,000	0
Other Assets, Miscellaneous, Current	4,387	1,180
Other Assets	$81,191	$1,692

Other_Assets_Rollforward_of_Mo

Other Assets Rollforward of Mortgage Servicing Rights (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Servicing Assets at Fair Value [Line Items]	'	'
Servicing Asset at Fair Value, Additions	$15,725	'
Servicing Asset at Fair Value, Changes in Fair Value Resulting from Changes in Valuation Inputs or Changes in Assumptions	0	'
Servicing Asset at Fair Value, Other Changes in Fair Value	-117	'
Servicing Asset at Fair Value, Amount	$15,608	$0

Other_Assets_Components_of_Ser

Other Assets Components of Servicing Revenue (Details) (USD $)	5 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2012
Contractually Specified Servicing Fees, Amount	'	$2,603	'
Ancillary Fee Income Generated by Servicing Financial Assets, Amount	'	735	'
Other Nonoperating Income (Expense)	'	12	'
Contractually Specified Servicing Fees, Late Fees, and Ancillary Fees Earned in Exchange for Servicing Financial Assets	'	3,350	'
Business Combination, Acquisition Related Costs	'	3,055	'
Labor and Related Expense	'	2,845	'
Other Expenses	'	1,589	'
Other Noninterest Expense	$0	$7,489	$0

Other_Liabilities_Schedule_of_

Other Liabilities Schedule of Other Liabilities (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Derivative, Collateral, Obligation to Return Cash	$32,463	$0
Due to Affiliate, Current	1,885	1,162
Payable for Equity Securities Purchased	4,581	0
Interest Payable, Current	4,401	5,009
Servicing Liability	15,608	0
Sales and Excise Tax Payable, Current	574	1,172
Other Accrued Liabilities, Current	10,203	273
Accounts payable and accrued expenses	$69,715	$7,616

Stockholders_Equity_Shares_Iss

Stockholders' Equity Shares Issued During Period (Details) (USD $)	3 Months Ended		5 Months Ended	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2013	Jun. 30, 2010	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2012	Jun. 30, 2012	Mar. 31, 2012
Class of Stock [Line Items]	'	'	'	'	'	'	'
Sale of Stock, Price Per Share	'	'	'	$25.40	$22.09	$22.74	$21.55
Common Stock, Shares, Issued	'	'	'	23,000	26,250	12,650	13,600
Stock Issued During Period, Value, New Issues	$292,780	$287,151	$199,121	$583,915	$579,931	'	'

Stockholders_Equity_Shares_Rep

Stockholders' Equity Shares Repurchased (Details) (USD $)	3 Months Ended			12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2013	Jun. 30, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012
Class of Stock [Line Items]	'	'	'	'	'
Stock Repurchase Program, Authorized Amount	$150	$100	$50	'	'
Stock Repurchase Program, Remaining Authorized Repurchase Amount	'	'	'	139.1	'
Stock Repurchased During Period, Shares	'	'	'	7.6	0.3
Treasury Stock Acquired, Average Cost Per Share	'	'	'	$20.23	$22.76
Payments for Repurchase of Common Stock	'	'	'	$154.10	$6.80

Stockholders_Equity_LongTerm_I

Stockholders' Equity Long-Term Incentive Plan (Details) (USD $)	5 Months Ended	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	$20	$25.23	$19.67
Share-based Compensation	$16,000	$135,000	$76,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	'	80,500	'
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	'	$200,000	$100,000
Each Director [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	1,500	1,500	'
Director [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	6,000	7,500	6,000

Income_Taxes_Tax_Characterizat

Income Taxes Tax Characterization of Dividends (USD $)	3 Months Ended								5 Months Ended	12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2012
Common Stock, Dividends, Per Share, Declared	$0.65	$0.70	$0.80	$0.90	$0.90	$0.90	$0.90	$0.90	$1	$3.05	$3.60
Ordinary Income [Member]	'	'	'	'	'	'	'	'	'	'	'
Common Stock, Dividends, Per Share, Declared	'	'	'	'	'	'	'	'	$1	$3.05	$3.60
Long-term Capital Gains [Member]	'	'	'	'	'	'	'	'	'	'	'
Common Stock, Dividends, Per Share, Declared	'	'	'	'	'	'	'	'	$0	$0	$0

Income_Taxes_Narrative_Details

Income Taxes Narrative (Details) (USD $)	3 Months Ended								5 Months Ended	12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2012
Undistributed Taxable Income	$39,800,000	'	'	'	'	'	'	'	'	$39,800,000	'
Excise tax	302,000	200,000	0	177,000	741,000	432,000	0	9,000	32,000	679,000	1,182,000
Operating Loss Carryforwards	-50,000,000	'	'	'	'	'	'	'	'	-50,000,000	'
Deferred Tax Assets, Net of Valuation Allowance	$21,000,000	'	'	'	'	'	'	'	'	$21,000,000	'

Management_Fees_and_Related_Pa1

Management Fees and Related Parties (Details) (USD $)	5 Months Ended	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2012
Related Party Transaction [Line Items]	'	'	'
Asset Management Costs	$1,188,000	$18,680,000	$9,638,000
Management Fee Payable	'	1,400,000	1,000,000
Expense Reimbursement to Manager	300,000	1,800,000	1,300,000
Accounts Payable, Related Parties, Current	'	100,000	200,000
External Management [Member]	'	'	'
Related Party Transaction [Line Items]	'	'	'
Asset Management Costs	$1,200,000	$18,700,000	$9,600,000

Quarterly_Results_Details

Quarterly Results (Details) (USD $)	3 Months Ended								5 Months Ended	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2012
Quarterly Results [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Investment Income, Interest	$69,694	$70,511	$63,927	$51,567	$49,768	$44,355	$34,695	$16,602	'	'	'
Interest Expense	10,656	10,949	9,113	8,036	8,288	7,329	4,786	1,664	1,737	38,754	22,067
Interest Income (Expense), Net	-59,038	-59,562	-54,814	-43,531	-41,480	-37,026	-29,909	-14,938	-14,677	-216,945	-123,353
Gain (Loss) on Investments	-62,310	-39,154	-102,160	-63,702	14,164	114,008	5,985	8,508	7,767	-267,326	142,665
Operating Expenses	13,676	6,506	7,007	6,221	4,514	4,360	3,665	2,117	2,743	33,410	14,656
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest	-16,948	13,902	-54,353	-26,392	51,130	146,674	32,229	21,329	'	'	'
Excise tax	302	200	0	177	741	432	0	9	32	679	1,182
Net income	($17,250)	$13,702	($54,353)	($26,569)	$50,389	$146,242	$32,229	$21,320	$19,669	($84,470)	$250,180
Earnings Per Share, Basic and Diluted	($0.33)	$0.25	($0.94)	($0.56)	$1.40	$4.03	$1.15	$1.82	$1.97	($1.59)	$8.90
Weighted Average Number of Shares Outstanding, Basic and Diluted	52,028	54,515	57,982	47,469	36,105	36,262	28,129	11,724	10,006	53,015	28,100
Common Stock, Dividends, Per Share, Declared	$0.65	$0.70	$0.80	$0.90	$0.90	$0.90	$0.90	$0.90	$1	$3.05	$3.60