Summary of Significant Accounting Policies	12 Months Ended
Dec. 31, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation and Consolidation Our consolidated financial statements are prepared in accordance with accounting principles generally accepted in the United States ("GAAP"). Our consolidated financial statements include the accounts of all subsidiaries and variable interest entities for which we are the primary beneficiary. Significant intercompany accounts and transactions have been eliminated. Adoption of Accounting Standard Updates As of January 1, 2018, we adopted Accounting Standards Update ("ASU") 2014-09, Revenue from Contracts with Customers (Topic 606), and ASU 2016-18, Statement of Cash Flows (Topic 230) - Restricted Cash. The adoption of ASU 2014-09 resulted in reclassification of expense reimbursements from an other operating expense offset to management fee income on the consolidated statements of comprehensive income. Net income was not impacted. The adoption of ASU 2016-18 resulted in the presentation of restricted cash with cash and cash equivalents on the consolidated statements of cash flows when reconciling the total beginning and ending amounts. Our prior period results have been revised to conform to the current presentation. 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 (loss) available (attributable) to common stockholders 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 and cash equivalents includes cash and cash equivalents pledged as collateral for clearing and executing trades, repurchase agreements and other borrowings, and interest rate swaps and other derivative instruments. Restricted cash and cash equivalents are carried at cost, which approximates fair value. Investment Securities Agency RMBS consist of residential mortgage pass-through securities and collateralized mortgage obligations ("CMOs") guaranteed by the Federal National Mortgage Association ("Fannie Mae"), Federal Home Loan Mortgage Corporation ("Freddie Mac," and together with Fannie Mae, the "GSEs") or the Government National Mortgage Association ("Ginnie Mae"). CRT securities are risk sharing instruments issued by the GSEs, and similarly structured transactions issued by third-party market participants, that transfer a portion of the risk associated with credit losses within pools of conventional residential mortgage loans from the GSEs and/or third parties to private investors. Unlike Agency RMBS, full repayment of the original principal balance of CRT securities is not guaranteed by a GSE or U.S. Government agency; rather, "credit risk transfer" is achieved by writing down the outstanding principal balance of the CRT securities if credit losses on a related pool of loans exceed certain thresholds. By reducing the amount that they are obligated to repay to holders of CRT securities, the GSEs and/or other third parties offset credit losses on the related loans. Non-Agency RMBS and CMBS (together, "Non-Agency MBS") are backed by residential and commercial mortgage loans, respectively, packaged and securitized by a private institution, such as a commercial bank. Non-Agency MBS typically benefit from credit enhancements derived from structural elements, such as subordination, overcollateralization or insurance, but nonetheless carry a higher level of credit exposure than Agency RMBS. Accounting Standards Codification ("ASC") Topic 320, Investments—Debt and Equity Securities, requires that at the time of purchase, we designate a security as held-to-maturity, available-for-sale or trading, depending on our ability and intent to hold such security to maturity. Alternatively, we may elect the fair value option of accounting for securities pursuant to ASC Topic 825, Financial Instruments. Prior to fiscal year 2017, we primarily designated our investment securities as available-for-sale. On January 1, 2017, we began electing the fair value option of accounting for all investment securities acquired after fiscal year 2016. Consequently, all of our securities are reported at fair value on our consolidated balance sheet. Unrealized gains and losses on securities classified as available-for-sale are reported in accumulated other comprehensive income ("OCI"). Unrealized gains and losses on securities for which we elected the fair value option or are classified as trading are reported in net income through other gain (loss) during the period in which they occur. Upon the sale of a security designated as available-for-sale, we determine the cost of the security and the amount of unrealized gains or losses to reclassify out of accumulated OCI into earnings based on the specific identification method. In our view, the election of the fair value option simplifies the accounting for investment securities and more appropriately reflects the results of our operations for a reporting period, as the fair value changes for these assets are presented in a manner consistent with the presentation and timing of the fair value changes of our derivative instruments. We estimate the fair value of our investment securities based on prices provided by multiple third-party pricing services and non-binding dealer quotes (collectively "pricing sources"). These pricing sources use various valuation approaches, including market and income approaches, using "Level 2" inputs. The pricing sources primarily utilize a matrix pricing technique that interpolates the estimated fair value of our Agency RMBS based on observed quoted prices for forward contracts in the Agency RMBS "to-be-announced" market ("TBA securities") of the same coupon, maturity and issuer, adjusted to reflect the specific characteristics of the pool of mortgages underlying the Agency security, which may include maximum loan balance, loan vintage, loan-to-value ratio, geography and other characteristics as may be appropriate. The pricing sources may also utilize discounted cash flow model-derived pricing techniques to estimate the fair value of investment securities. Such models incorporate market-based discount rate assumptions based on observable inputs such as recent trading activity, credit data, volatility statistics, benchmark interest rate curves and other market data that are current as of the measurement date and may include certain unobservable inputs, such as assumptions of future levels of prepayment, defaults and loss severities. We review the pricing estimates obtained from the pricing sources and perform procedures to validate their reasonableness. Refer to Note 8 for further discussion of fair value measurements. We evaluate our investments designated as available-for-sale for other-than-temporary impairment ("OTTI") on at least a quarterly basis. The determination of whether a security is other-than-temporarily impaired may involve judgments and assumptions based on subjective and objective factors. When a security is impaired, an OTTI is considered to have occurred if any one of the following three conditions exists as of the financial reporting date: (i) we intend to sell the security (that is, a decision has been made to sell the security), (ii) it is more likely than not that we will be required to sell the security before recovery of its amortized cost basis or (iii) we do not expect to recover the security's amortized cost basis, even if we do not intend to sell the security and it is not more likely than not that we will be required to sell the security. A general allowance for unidentified impairments in a portfolio of securities is not permitted. If either of the first two conditions exists as of the financial reporting date, the entire amount of the impairment loss, if any, is recognized in earnings as a realized loss and the cost basis of the security is adjusted to its fair value. If the third condition exists, the OTTI is separated into (i) the amount relating to credit loss (the "credit component") and (ii) the amount relating to all other factors (the "non-credit components"). Only the credit component is recognized in earnings, with the non-credit components recognized in OCI. We did not recognize OTTI charges on our investment securities for fiscal years 2018, 2017 or 2016. Interest Income Interest income is accrued based on the outstanding principal amount of the investment securities and their contractual terms. Premiums or discounts associated with the purchase of Agency RMBS and non-Agency MBS 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 in accordance with ASC Subtopic 310-20, Receivables—Nonrefundable Fees and Other Costs. We estimate long-term prepayment speeds of our mortgage securities using a third-party service and market data. The third-party service provider estimates prepayment speeds using models that incorporate the forward yield curve, current mortgage rates, mortgage rates of the outstanding loans, age and size of the outstanding loans, loan-to-value ratios, interest rate 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 third-party estimates. We review our actual and anticipated prepayment experience on at least a quarterly basis and effective yields are recalculated when differences arise between (i) our previously estimated future prepayments and (ii) actual prepayments to date and our current estimated future prepayments. If the actual and estimated 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 CRT securities and non-Agency MBS that are not of high credit quality, we determine an effective yield based on our estimate of the timing and amount of future cash flows and our cost basis. Our initial cash flow estimates for these investments are based on our observations of current information and events and include assumptions related to interest rates, prepayment rates and the impact of default and severity rates on the timing and amount of credit losses. On at least a quarterly basis, we review the estimated cash flows and make appropriate adjustments based on inputs and analysis received from external sources, internal models, and our judgment regarding such inputs and other factors. Any resulting changes in effective yield are recognized prospectively based on the current amortized cost of the investment adjusted for credit impairments, if any. Repurchase Agreements We finance the acquisition of securities for our investment portfolio primarily through repurchase transactions under master repurchase agreements. Pursuant to ASC Topic 860, Transfers and Servicing, we account for repurchase transactions as collateralized financing transactions, which are carried at their contractual amounts (cost), plus accrued interest. Our repurchase agreements typically have maturities of less than one year but may extend up to five years or more. Interest rates on our repurchase agreements generally correspond to one or three-month LIBOR plus or minus a fixed spread. The fair value of our repurchase agreements is assumed to equal cost as the interest rates are considered to be at market. Reverse Repurchase Agreements and Obligation to Return Securities Borrowed under Reverse Repurchase Agreements We borrow securities to cover short sales of U.S. Treasury securities through reverse repurchase transactions under our master repurchase agreements (see Derivative 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 typically have maturities of 30 days or less. The fair value of our reverse repurchase agreements is assumed to equal cost as the interest rates are considered to be at market. Derivative Instruments We use a variety of derivative instruments to hedge a portion of our exposure to market risks, including interest rate, prepayment, extension and liquidity risks. The objective of our risk management strategy is to reduce fluctuations in net book value over a range of interest rate scenarios. In particular, we attempt to mitigate the risk of the cost of our variable rate liabilities increasing during a period of rising interest rates. The primary instruments that we use are interest rate swaps, options to enter into interest rate swaps ("swaptions"), U.S. Treasury securities and U.S. Treasury futures contracts. We also use forward contracts in the Agency RMBS "to-be-announced" market, or TBA securities, to invest in and finance Agency securities as well as to periodically reduce our exposure to Agency RMBS. We account for derivative instruments in accordance with ASC Topic 815, Derivatives and Hedging ("ASC 815"). ASC 815 requires an entity to recognize all derivatives as either assets or liabilities in our accompanying consolidated balance sheets and to measure those instruments at fair value. None of our derivative instruments have been designated as hedging instruments for accounting purposes under the provisions of ASC 815, consequently changes in the fair value of our derivative instruments are reported in gain (loss) on derivative instruments and other securities, net in our consolidated statements of comprehensive income. Our derivative agreements generally contain provisions that allow for netting or setting off derivative assets and liabilities with the counterparty; however, we report related assets and liabilities on a gross basis in our consolidated balance sheets. Derivative instruments in a gain position are reported as derivative assets at fair value and derivative instruments in a loss position are reported as derivative liabilities at fair value in our consolidated balance sheets. Changes in fair value of derivative instruments and periodic settlements related to our derivative instruments are recorded in gain (loss) on derivative instruments and other securities, net in our consolidated statements of comprehensive income. 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. The use of derivative instruments creates exposure to credit risk relating to potential losses that could be recognized if the counterparties to these instruments fail to perform their obligations under the contracts. Our derivative agreements require that we post or receive collateral to mitigate such risk. We also attempt to minimize our risk of loss by limiting our counterparties to registered central clearing exchanges and 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 economically hedge the variable cash flows associated with our borrowings made under repurchase agreements. Under our interest rate swap agreements, we typically pay a fixed rate and receive a floating rate based on one or three-month LIBOR ("payer swaps") with terms up to 20 years. The majority of our interest rate swaps are centrally cleared through a registered commodities exchange. We value centrally cleared interest rate swaps using the daily settlement price, or fair value, determined by the clearing exchange based on a pricing model that references observable market inputs, including LIBOR, swap rates and the forward yield curve. Our centrally cleared swaps require that we post an "initial margin" amount determined by the clearing exchange, which is generally intended to be set at a level sufficient to protect the exchange from the interest rate swap's maximum estimated single-day price movement. We also exchange daily settlements of "variation margin" based upon changes in fair value, as measured by the exchange. Pursuant to rules governing central clearing activities, we recognize variation margin settlements as a direct reduction of the carrying value of the interest rate swap asset or liability. We value non-centrally cleared swaps using a combination of third-party valuations obtained from pricing services and the swap counterparty. The third-party valuations are model-driven using observable inputs, including LIBOR, swap rates and the forward yield curve. We also consider 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 assess 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. Interest rate swaptions We purchase interest rate swaptions to help mitigate the potential impact of larger, more rapid changes in interest rates on the performance of our investment portfolio. Interest rate swaptions provide us the option to enter into an interest rate swap agreement for a predetermined notional amount, stated term and pay and receive interest rates in the future. Our interest rate swaption agreements are not subject to central clearing. The premium paid for interest rate swaptions is reported as an asset in our consolidated balance sheets. 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. The difference between the premium paid and the fair value of the swaption is reported in gain (loss) on derivative instruments and other securities, net in our consolidated statements of comprehensive income. If a swaption expires unexercised, the realized loss on the swaption would be equal to the premium paid. If we sell or exercise a swaption, the realized gain or loss on the swaption would be equal to the difference between the cash or the fair value of the underlying interest rate swap and the premium paid. TBA securities A TBA security is a forward contract for the purchase or sale of Agency RMBS at a predetermined price, face amount, issuer, coupon and stated maturity on an agreed-upon future date. The specific Agency RMBS to be delivered into the contract are not known until shortly before the settlement date. We may choose, prior to settlement, to move the settlement of these securities out to a later date by entering into an offsetting TBA position, net settling the offsetting positions for cash, and simultaneously purchasing or selling a similar TBA contract for a later settlement date (together referred to as a "dollar roll transaction"). The Agency securities purchased or sold for a forward settlement date are typically priced at a discount to equivalent securities settling in the current month. This difference, or "price drop," is the economic equivalent of interest income on the underlying Agency securities, less an implied funding cost, over the forward settlement period (referred to as "dollar roll income"). Consequently, forward purchases of Agency securities and dollar roll transactions represent a form of off-balance sheet financing. We account for TBA contracts as derivative instruments since either the TBA contracts do not settle in the shortest period of time possible or we cannot assert that it is probable at inception and throughout the term of the TBA contract that we will physically settle the contract on the settlement date. We account for TBA dollar roll transactions as a series of derivative transactions. We estimate the fair value of TBA securities based on similar methods used to value our Agency RMBS securities. U.S. Treasury securities We use U.S. Treasury securities and U.S. Treasury futures contracts to mitigate the potential impact of changes in interest rates on the performance of our portfolio. We borrow U.S. Treasury securities under reverse repurchase agreements to cover short sales of U.S. Treasury securities. We account for these as securities borrowing transactions and recognize an obligation to return the borrowed securities at fair value on our accompanying consolidated balance sheets based on the value of the underlying U.S. Treasury security as of the reporting date. Gains and losses associated with U.S. Treasury securities and U.S. Treasury futures contracts are recognized in gain (loss) on derivative instruments and other securities, net in our consolidated statements of comprehensive income. Variable Interest Entities ASC Topic 810, Consolidation ("ASC 810"), requires an enterprise to consolidate a variable interest entity ("VIE") if it is deemed the primary beneficiary of the VIE. Further, ASC 810 requires a qualitative assessment to determine the primary beneficiary of a VIE and ongoing assessments of whether an enterprise is the primary beneficiary of a VIE as well as additional disclosures for entities that have variable interests in VIEs. Prior to fiscal year 2016, we entered into transactions involving CMO trusts for which we determined we are the primary beneficiary given our level of control in the selection of Agency RMBS assets transferred to the CMO trust. Agency RMBS transferred to consolidated VIEs are reported on our consolidated balance sheets in Agency securities transferred to consolidated VIEs, at fair value and can only be used to settle the obligations of each respective VIE. We elected the option to account for the consolidated debt at fair value, with changes in fair value reflected in earnings during the period in which they occur, because we believe this election more appropriately reflects our financial position as both the consolidated assets and consolidated debt are presented in a consistent manner on our consolidated balance sheets. We estimate the fair value of the consolidated debt based on the fair value of the Agency RMBS transferred to consolidated VIEs, less the fair value of our retained interests, which are measured on a market approach using "Level 2" inputs from third-party pricing services and dealer quotes. The fair value of the Agency RMBS transferred to the consolidated VIEs and the fair value of our retained interests are based on more observable inputs than inputs used to independently determine the value of our consolidated debt. As of December 31, 2018 and 2017, debt of consolidated VIEs, at fair value, was $275 million and $357 million, respectively, had a weighted average interest rate of LIBOR plus 40 and 37 basis points, respectively, and an estimated weighted average life of 6.1 years and 5.7 years, respectively. Stock-Based Compensation We measure and recognize compensation expense for all stock-based payment awards made to employees and independent directors based on their fair values. Stock-based awards issued under our equity incentive plan include time-based and performance-based restricted stock unit awards ("RSU" and "PSU" awards, respectively). An RSU and PSU awards are an agreement to issue an equivalent number of shares of our common stock, plus any equivalent shares for dividends declared on our common stock, at the time the award vests, or later if distribution of such shares has been deferred beyond the vesting date. RSU awards vest over a specified service period. PSU awards vest over a specified service period subject to achieving long-term performance criteria. We value RSU and PSU awards based on the fair value of our common stock on the date of grant. Compensation expense is recognized over each award’s respective service period. In the case of PSU awards, we estimate the probability that the performance criteria will be achieved and recognize expense only for those awards expected to vest. We reevaluate our estimates each reporting period and recognize a cumulative effect adjustment to expense if our estimates change from the prior period. We do not estimate forfeiture rates; rather, we adjust for forfeitures in the periods in which they occur. Shares underlying RSU and PSU awards are issued on the vesting dates, or later if distribution of such shares has been deferred beyond the vesting date, net of any minimum statutory tax withholdings to be paid by us on behalf of our employees. As a result, the actual number of shares issued will be fewer than the actual number of awards outstanding. When awards vest, we record a liability for withholding amounts to be paid by us as a reduction to additional paid-in capital. Goodwill and Other Intangible Asset, Net Goodwill is the cost of an acquisition in excess of the fair value of identified assets acquired and liabilities assumed and is recognized as an asset on our consolidated balance sheets. Acquired intangible assets that do not meet the criteria for recognition as a separate asset are included in goodwill. Goodwill is not subject to amortization but must be tested for impairment at least annually. Intangible assets meeting the criteria for recognition as separate assets are recorded at their respective fair market values at the date of acquisition. Intangible assets with an estimated useful life are amortized over their expected useful life. As of December 31, 2018, we had $526 million of goodwill and, as of December 31, 2017, we had $526 million of goodwill and an intangible asset of $25 million associated with our management of MTGE Investment Corp. ("MTGE") (Nasdaq: MTGE) reported in goodwill and other intangible asset, net in our accompanying consolidated balance sheets related to our acquisition of AMM. We test goodwill for impairment on an annual basis and at interim periods when events or circumstances may make it more likely than not that an impairment has occurred. If a qualitative analysis indicates that there may be an impairment, a quantitative analysis is performed. The quantitative analysis requires that we compare the carrying value of the identified reporting unit comprising the goodwill to the reporting unit's fair value. If the reporting units' carrying value is greater than its fair value, an impairment charge is recognized to the extent the carrying amount of the reporting unit exceeds its fair value. During fiscal years 2018, 2017 or 2016, we did not recognize a goodwill impairment charge. During fiscal year 2018, we wrote-off the unamortized intangible asset balance due to the sale of MTGE to a third-party and corresponding termination of its management agreement (see Note 12). Loss Contingencies We evaluate the existence of any pending or threatened litigation or other potential claims against the Company in accordance with ASC Topic 450, Contingencies, which requires that we assess the likelihood and range of potential outcomes of any such matters. We are the defendant in three stockholder derivative lawsuits alleging that certain of our current and former directors and officers breached fiduciary duties and wasted corporate assets relating to past renewals of the management agreement with our former external manager and the internalization of our management on July 1, 2016. Although the outcomes of these cases cannot be predicted with certainty, we do not believe that these cases have merit or will result in a material liability, and, as of December 31, 2018, we did not accrue a loss contingency related to these matters. Recent Accounting Pronouncements We consider the applicability and impact of all ASUs issued by the Financial Accounting Standards Board. ASUs not listed below were determined to be either not applicable, are not expected to have a significant impact on our consolidated financial statements when adopted or did not have a significant impact on our consolidated financial statements upon adoption. ASU 2016-13, Financial Instruments - Credit Losses (Topic 326): ASU 2016-13 changes the impairment model for most financial assets and certain other instruments. Allowances for credit losses on available-for-sale debt securities will be recognized, rather than direct reductions in the amortized cost of the investments. The new model also requires the estimation of lifetime expected credit losses and corresponding recognition of allowance for losses on trade and other receivables, held-to-maturity debt securities, loans, and other instruments held at amortized cost. The ASU requires certain recurring disclosures and is effective for annual periods, and interim periods within those annual periods, beginning on or after December 15, 2019, with early adoption permitted for annual periods, and interim periods within those annual periods, beginning on or after December 15, 2018. ASU 2016-13 is not expected to have a significant impact on our consolidated financial statements. ASU 2016-2, Leases (Topic 842): ASU 2016-2 requires lessees to recognize virtually all their leases on the balance sheet by recording a right-of-use asset and a lease liability. The lease liability will be measured at the present value of lease payments and the right-of-use asset will be based on the lease liability value, subject to adjustments. Leases can be classified as either operating leases or finance leases. Operating leases will result in straight-line lease expense, while finance leases will result in front-loaded expense. This guidance is effective for the Company on January 1, 2019. We have evaluated ASU 2016-2 and determined that it will not have a significant impact on our consolidated financial statements.

Summary of Significant Accounting Policies

Basis of Presentation and Consolidation

Our consolidated financial statements are prepared in accordance with accounting principles generally accepted in the United States ("GAAP"). Our consolidated financial statements include the accounts of all subsidiaries and variable interest entities for which we are the primary beneficiary. Significant intercompany accounts and transactions have been eliminated.

Adoption of Accounting Standard Updates

As of January 1, 2018, we adopted Accounting Standards Update ("ASU") 2014-09, Revenue from Contracts with Customers (Topic 606), and ASU 2016-18, Statement of Cash Flows (Topic 230) - Restricted Cash. The adoption of ASU 2014-09 resulted in reclassification of expense reimbursements from an other operating expense offset to management fee income on the consolidated statements of comprehensive income. Net income was not impacted. The adoption of ASU 2016-18 resulted in the presentation of restricted cash with cash and cash equivalents on the consolidated statements of cash flows when reconciling the total beginning and ending amounts. Our prior period results have been revised to conform to the current presentation.

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 (loss) available (attributable) to common stockholders 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 and cash equivalents includes cash and cash equivalents pledged as collateral for clearing and executing trades, repurchase agreements and other borrowings, and interest rate swaps and other derivative instruments. Restricted cash and cash equivalents are carried at cost, which approximates fair value.

Investment Securities

Agency RMBS consist of residential mortgage pass-through securities and collateralized mortgage obligations ("CMOs") guaranteed by the Federal National Mortgage Association ("Fannie Mae"), Federal Home Loan Mortgage Corporation ("Freddie Mac," and together with Fannie Mae, the "GSEs") or the Government National Mortgage Association ("Ginnie Mae").

CRT securities are risk sharing instruments issued by the GSEs, and similarly structured transactions issued by third-party market participants, that transfer a portion of the risk associated with credit losses within pools of conventional residential mortgage loans from the GSEs and/or third parties to private investors. Unlike Agency RMBS, full repayment of the original principal balance of CRT securities is not guaranteed by a GSE or U.S. Government agency; rather, "credit risk transfer" is achieved by writing down the outstanding principal balance of the CRT securities if credit losses on a related pool of loans exceed certain thresholds. By reducing the amount that they are obligated to repay to holders of CRT securities, the GSEs and/or other third parties offset credit losses on the related loans.

Non-Agency RMBS and CMBS (together, "Non-Agency MBS") are backed by residential and commercial mortgage loans, respectively, packaged and securitized by a private institution, such as a commercial bank. Non-Agency MBS typically benefit from credit enhancements derived from structural elements, such as subordination, overcollateralization or insurance, but nonetheless carry a higher level of credit exposure than Agency RMBS.

Accounting Standards Codification ("ASC") Topic 320, Investments—Debt and Equity Securities, requires that at the time of purchase, we designate a security as held-to-maturity, available-for-sale or trading, depending on our ability and intent to hold such security to maturity. Alternatively, we may elect the fair value option of accounting for securities pursuant to ASC Topic 825, Financial Instruments. Prior to fiscal year 2017, we primarily designated our investment securities as available-for-sale. On January 1, 2017, we began electing the fair value option of accounting for all investment securities acquired after fiscal year 2016. Consequently, all of our securities are reported at fair value on our consolidated balance sheet. Unrealized gains and losses on securities classified as available-for-sale are reported in accumulated other comprehensive income ("OCI"). Unrealized gains and losses on securities for which we elected the fair value option or are classified as trading are reported in net income through other gain (loss) during the period in which they occur. Upon the sale of a security designated as available-for-sale, we determine the cost of the security and the amount of unrealized gains or losses to reclassify out of accumulated OCI into earnings based on the specific identification method.

In our view, the election of the fair value option simplifies the accounting for investment securities and more appropriately reflects the results of our operations for a reporting period, as the fair value changes for these assets are presented in a manner consistent with the presentation and timing of the fair value changes of our derivative instruments.

We estimate the fair value of our investment securities based on prices provided by multiple third-party pricing services and non-binding dealer quotes (collectively "pricing sources"). These pricing sources use various valuation approaches, including market and income approaches, using "Level 2" inputs. The pricing sources primarily utilize a matrix pricing technique that interpolates the estimated fair value of our Agency RMBS based on observed quoted prices for forward contracts in the Agency RMBS "to-be-announced" market ("TBA securities") of the same coupon, maturity and issuer, adjusted to reflect the specific characteristics of the pool of mortgages underlying the Agency security, which may include maximum loan balance, loan vintage, loan-to-value ratio, geography and other characteristics as may be appropriate. The pricing sources may also utilize discounted cash flow model-derived pricing techniques to estimate the fair value of investment securities. Such models incorporate market-based discount rate assumptions based on observable inputs such as recent trading activity, credit data, volatility statistics, benchmark interest rate curves and other market data that are current as of the measurement date and may include certain unobservable inputs, such as assumptions of future levels of prepayment, defaults and loss severities. We review the pricing estimates obtained from the pricing sources and perform procedures to validate their reasonableness. Refer to Note 8 for further discussion of fair value measurements.

We evaluate our investments designated as available-for-sale for other-than-temporary impairment ("OTTI") on at least a quarterly basis. The determination of whether a security is other-than-temporarily impaired may involve judgments and assumptions based on subjective and objective factors. When a security is impaired, an OTTI is considered to have occurred if any one of the following three conditions exists as of the financial reporting date: (i) we intend to sell the security (that is, a decision has been made to sell the security), (ii) it is more likely than not that we will be required to sell the security before recovery of its amortized cost basis or (iii) we do not expect to recover the security's amortized cost basis, even if we do not intend to sell the security and it is not more likely than not that we will be required to sell the security. A general allowance for unidentified impairments in a portfolio of securities is not permitted. If either of the first two conditions exists as of the financial reporting date, the entire amount of the impairment loss, if any, is recognized in earnings as a realized loss and the cost basis of the security is adjusted to its fair value. If the third condition exists, the OTTI is separated into (i) the amount relating to credit loss (the "credit component") and (ii) the amount relating to all other factors (the "non-credit components"). Only the credit component is recognized in earnings, with the non-credit components recognized in OCI. We did not recognize OTTI charges on our investment securities for fiscal years 2018, 2017 or 2016.

Interest Income

Interest income is accrued based on the outstanding principal amount of the investment securities and their contractual terms. Premiums or discounts associated with the purchase of Agency RMBS and non-Agency MBS 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 in accordance with ASC Subtopic 310-20, Receivables—Nonrefundable Fees and Other Costs.

We estimate long-term prepayment speeds of our mortgage securities using a third-party service and market data. The third-party service provider estimates prepayment speeds using models that incorporate the forward yield curve, current mortgage rates, mortgage rates of the outstanding loans, age and size of the outstanding loans, loan-to-value ratios, interest rate 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 third-party estimates. We review our actual and anticipated prepayment experience on at least a quarterly basis and effective yields are recalculated when differences arise between (i) our previously estimated future prepayments and (ii) actual prepayments to date and our current estimated future prepayments. If the actual and estimated 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 CRT securities and non-Agency MBS that are not of high credit quality, we determine an effective yield based on our estimate of the timing and amount of future cash flows and our cost basis. Our initial cash flow estimates for these investments are based on our observations of current information and events and include assumptions related to interest rates, prepayment rates and the impact of default and severity rates on the timing and amount of credit losses. On at least a quarterly basis, we review the estimated cash flows and make appropriate adjustments based on inputs and analysis received from external sources, internal models, and our judgment regarding such inputs and other factors. Any resulting changes in effective yield are recognized prospectively based on the current amortized cost of the investment adjusted for credit impairments, if any.

Repurchase Agreements

We finance the acquisition of securities for our investment portfolio primarily through repurchase transactions under master repurchase agreements. Pursuant to ASC Topic 860, Transfers and Servicing, we account for repurchase transactions as collateralized financing transactions, which are carried at their contractual amounts (cost), plus accrued interest. Our repurchase agreements typically have maturities of less than one year but may extend up to five years or more. Interest rates on our repurchase agreements generally correspond to one or three-month LIBOR plus or minus a fixed spread. The fair value of our repurchase agreements is assumed to equal cost as the interest rates are considered to be at market.

Reverse Repurchase Agreements and Obligation to Return Securities Borrowed under Reverse Repurchase Agreements

We borrow securities to cover short sales of U.S. Treasury securities through reverse repurchase transactions under our master repurchase agreements (see Derivative 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 typically have maturities of 30 days or less. The fair value of our reverse repurchase agreements is assumed to equal cost as the interest rates are considered to be at market.

Derivative Instruments

We use a variety of derivative instruments to hedge a portion of our exposure to market risks, including interest rate, prepayment, extension and liquidity risks. The objective of our risk management strategy is to reduce fluctuations in net book value over a range of interest rate scenarios. In particular, we attempt to mitigate the risk of the cost of our variable rate liabilities increasing during a period of rising interest rates. The primary instruments that we use are interest rate swaps, options to enter into interest rate swaps ("swaptions"), U.S. Treasury securities and U.S. Treasury futures contracts. We also use forward contracts in the Agency RMBS "to-be-announced" market, or TBA securities, to invest in and finance Agency securities as well as to periodically reduce our exposure to Agency RMBS.

We account for derivative instruments in accordance with ASC Topic 815, Derivatives and Hedging ("ASC 815"). ASC 815 requires an entity to recognize all derivatives as either assets or liabilities in our accompanying consolidated balance sheets and to measure those instruments at fair value. None of our derivative instruments have been designated as hedging instruments for accounting purposes under the provisions of ASC 815, consequently changes in the fair value of our derivative instruments are reported in gain (loss) on derivative instruments and other securities, net in our consolidated statements of comprehensive income.

Our derivative agreements generally contain provisions that allow for netting or setting off derivative assets and liabilities with the counterparty; however, we report related assets and liabilities on a gross basis in our consolidated balance sheets. Derivative instruments in a gain position are reported as derivative assets at fair value and derivative instruments in a loss position are reported as derivative liabilities at fair value in our consolidated balance sheets. Changes in fair value of derivative instruments and periodic settlements related to our derivative instruments are recorded in gain (loss) on derivative instruments and other securities, net in our consolidated statements of comprehensive income. 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.

The use of derivative instruments creates exposure to credit risk relating to potential losses that could be recognized if the counterparties to these instruments fail to perform their obligations under the contracts. Our derivative agreements require that we post or receive collateral to mitigate such risk. We also attempt to minimize our risk of loss by limiting our counterparties to registered central clearing exchanges and 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 economically hedge the variable cash flows associated with our borrowings made under repurchase agreements. Under our interest rate swap agreements, we typically pay a fixed rate and receive a floating rate based on one or three-month LIBOR ("payer swaps") with terms up to 20 years. The majority of our interest rate swaps are centrally cleared through a registered commodities exchange. We value centrally cleared interest rate swaps using the daily settlement price, or fair value, determined by the clearing exchange based on a pricing model that references observable market inputs, including LIBOR, swap rates and the forward yield curve. Our centrally cleared swaps require that we post an "initial margin" amount determined by the clearing exchange, which is generally intended to be set at a level sufficient to protect the exchange from the interest rate swap's maximum estimated single-day price movement. We also exchange daily settlements of "variation margin" based upon changes in fair value, as measured by the exchange. Pursuant to rules governing central clearing activities, we recognize variation margin settlements as a direct reduction of the carrying value of the interest rate swap asset or liability.

We value non-centrally cleared swaps using a combination of third-party valuations obtained from pricing services and the swap counterparty. The third-party valuations are model-driven using observable inputs, including LIBOR, swap rates and the forward yield curve. We also consider 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 assess 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.

Interest rate swaptions

We purchase interest rate swaptions to help mitigate the potential impact of larger, more rapid changes in interest rates on the performance of our investment portfolio. Interest rate swaptions provide us the option to enter into an interest rate swap agreement for a predetermined notional amount, stated term and pay and receive interest rates in the future. Our interest rate swaption agreements are not subject to central clearing. The premium paid for interest rate swaptions is reported as an asset in our consolidated balance sheets. 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. The difference between the premium paid and the fair value of the swaption is reported in gain (loss) on derivative instruments and other securities, net in our consolidated statements of comprehensive income. If a swaption expires unexercised, the realized loss on the swaption would be equal to the premium paid. If we sell or exercise a swaption, the realized gain or loss on the swaption would be equal to the difference between the cash or the fair value of the underlying interest rate swap and the premium paid.

TBA securities

A TBA security is a forward contract for the purchase or sale of Agency RMBS at a predetermined price, face amount, issuer, coupon and stated maturity on an agreed-upon future date. The specific Agency RMBS to be delivered into the contract are not known until shortly before the settlement date. We may choose, prior to settlement, to move the settlement of these securities out to a later date by entering into an offsetting TBA position, net settling the offsetting positions for cash, and simultaneously purchasing or selling a similar TBA contract for a later settlement date (together referred to as a "dollar roll transaction"). The Agency securities purchased or sold for a forward settlement date are typically priced at a discount to equivalent securities settling in the current month. This difference, or "price drop," is the economic equivalent of interest income on the underlying Agency securities, less an implied funding cost, over the forward settlement period (referred to as "dollar roll income"). Consequently, forward purchases of Agency securities and dollar roll transactions represent a form of off-balance sheet financing.

We account for TBA contracts as derivative instruments since either the TBA contracts do not settle in the shortest period of time possible or we cannot assert that it is probable at inception and throughout the term of the TBA contract that we will physically settle the contract on the settlement date. We account for TBA dollar roll transactions as a series of derivative transactions. We estimate the fair value of TBA securities based on similar methods used to value our Agency RMBS securities.

U.S. Treasury securities

We use U.S. Treasury securities and U.S. Treasury futures contracts to mitigate the potential impact of changes in interest rates on the performance of our portfolio. We borrow U.S. Treasury securities under reverse repurchase agreements to cover short sales of U.S. Treasury securities. We account for these as securities borrowing transactions and recognize an obligation to return the borrowed securities at fair value on our accompanying consolidated balance sheets based on the value of the underlying U.S. Treasury security as of the reporting date. Gains and losses associated with U.S. Treasury securities and U.S. Treasury futures contracts are recognized in gain (loss) on derivative instruments and other securities, net in our consolidated statements of comprehensive income.

Variable Interest Entities

ASC Topic 810, Consolidation ("ASC 810"), requires an enterprise to consolidate a variable interest entity ("VIE") if it is deemed the primary beneficiary of the VIE. Further, ASC 810 requires a qualitative assessment to determine the primary beneficiary of a VIE and ongoing assessments of whether an enterprise is the primary beneficiary of a VIE as well as additional disclosures for entities that have variable interests in VIEs. Prior to fiscal year 2016, we entered into transactions involving CMO trusts for which we determined we are the primary beneficiary given our level of control in the selection of Agency RMBS assets transferred to the CMO trust. Agency RMBS transferred to consolidated VIEs are reported on our consolidated balance sheets in Agency securities transferred to consolidated VIEs, at fair value and can only be used to settle the obligations of each respective VIE.

We elected the option to account for the consolidated debt at fair value, with changes in fair value reflected in earnings during the period in which they occur, because we believe this election more appropriately reflects our financial position as both the consolidated assets and consolidated debt are presented in a consistent manner on our consolidated balance sheets. We estimate the fair value of the consolidated debt based on the fair value of the Agency RMBS transferred to consolidated VIEs, less the fair value of our retained interests, which are measured on a market approach using "Level 2" inputs from third-party pricing services and dealer quotes. The fair value of the Agency RMBS transferred to the consolidated VIEs and the fair value of our retained interests are based on more observable inputs than inputs used to independently determine the value of our consolidated debt. As of December 31, 2018 and 2017, debt of consolidated VIEs, at fair value, was $275 million and $357 million, respectively, had a weighted average interest rate of LIBOR plus 40 and 37 basis points, respectively, and an estimated weighted average life of 6.1 years and 5.7 years, respectively.

Stock-Based Compensation

We measure and recognize compensation expense for all stock-based payment awards made to employees and independent directors based on their fair values. Stock-based awards issued under our equity incentive plan include time-based and performance-based restricted stock unit awards ("RSU" and "PSU" awards, respectively). An RSU and PSU awards are an agreement to issue an equivalent number of shares of our common stock, plus any equivalent shares for dividends declared on our common stock, at the time the award vests, or later if distribution of such shares has been deferred beyond the vesting date. RSU awards vest over a specified service period. PSU awards vest over a specified service period subject to achieving long-term performance criteria.

We value RSU and PSU awards based on the fair value of our common stock on the date of grant. Compensation expense is recognized over each award’s respective service period. In the case of PSU awards, we estimate the probability that the performance criteria will be achieved and recognize expense only for those awards expected to vest. We reevaluate our estimates each reporting period and recognize a cumulative effect adjustment to expense if our estimates change from the prior period. We do not estimate forfeiture rates; rather, we adjust for forfeitures in the periods in which they occur.

Shares underlying RSU and PSU awards are issued on the vesting dates, or later if distribution of such shares has been deferred beyond the vesting date, net of any minimum statutory tax withholdings to be paid by us on behalf of our employees. As a result, the actual number of shares issued will be fewer than the actual number of awards outstanding. When awards vest, we record a liability for withholding amounts to be paid by us as a reduction to additional paid-in capital.

Goodwill and Other Intangible Asset, Net

Goodwill is the cost of an acquisition in excess of the fair value of identified assets acquired and liabilities assumed and is recognized as an asset on our consolidated balance sheets. Acquired intangible assets that do not meet the criteria for recognition as a separate asset are included in goodwill. Goodwill is not subject to amortization but must be tested for impairment at least annually. Intangible assets meeting the criteria for recognition as separate assets are recorded at their respective fair market values at the date of acquisition. Intangible assets with an estimated useful life are amortized over their expected useful life.

As of December 31, 2018, we had $526 million of goodwill and, as of December 31, 2017, we had $526 million of goodwill and an intangible asset of $25 million associated with our management of MTGE Investment Corp. ("MTGE") (Nasdaq: MTGE) reported in goodwill and other intangible asset, net in our accompanying consolidated balance sheets related to our acquisition of AMM. We test goodwill for impairment on an annual basis and at interim periods when events or circumstances may make it more likely than not that an impairment has occurred. If a qualitative analysis indicates that there may be an impairment, a quantitative analysis is performed. The quantitative analysis requires that we compare the carrying value of the identified reporting unit comprising the goodwill to the reporting unit's fair value. If the reporting units' carrying value is greater than its fair value, an impairment charge is recognized to the extent the carrying amount of the reporting unit exceeds its fair value. During fiscal years 2018, 2017 or 2016, we did not recognize a goodwill impairment charge. During fiscal year 2018, we wrote-off the unamortized intangible asset balance due to the sale of MTGE to a third-party and corresponding termination of its management agreement (see Note 12).

Loss Contingencies

We evaluate the existence of any pending or threatened litigation or other potential claims against the Company in accordance with ASC Topic 450, Contingencies, which requires that we assess the likelihood and range of potential outcomes of any such matters. We are the defendant in three stockholder derivative lawsuits alleging that certain of our current and former directors and officers breached fiduciary duties and wasted corporate assets relating to past renewals of the management agreement with our former external manager and the internalization of our management on July 1, 2016. Although the outcomes of these cases cannot be predicted with certainty, we do not believe that these cases have merit or will result in a material liability, and, as of December 31, 2018, we did not accrue a loss contingency related to these matters.

Recent Accounting Pronouncements

We consider the applicability and impact of all ASUs issued by the Financial Accounting Standards Board. ASUs not listed below were determined to be either not applicable, are not expected to have a significant impact on our consolidated financial statements when adopted or did not have a significant impact on our consolidated financial statements upon adoption.

ASU 2016-13, Financial Instruments - Credit Losses (Topic 326): ASU 2016-13 changes the impairment model for most financial assets and certain other instruments. Allowances for credit losses on available-for-sale debt securities will be recognized, rather than direct reductions in the amortized cost of the investments. The new model also requires the estimation of lifetime expected credit losses and corresponding recognition of allowance for losses on trade and other receivables, held-to-maturity debt securities, loans, and other instruments held at amortized cost. The ASU requires certain recurring disclosures and is effective for annual periods, and interim periods within those annual periods, beginning on or after December 15, 2019, with early adoption permitted for annual periods, and interim periods within those annual periods, beginning on or after December 15, 2018. ASU 2016-13 is not expected to have a significant impact on our consolidated financial statements.

ASU 2016-2, Leases (Topic 842): ASU 2016-2 requires lessees to recognize virtually all their leases on the balance sheet by recording a right-of-use asset and a lease liability. The lease liability will be measured at the present value of lease payments and the right-of-use asset will be based on the lease liability value, subject to adjustments. Leases can be classified as either operating leases or finance leases. Operating leases will result in straight-line lease expense, while finance leases will result in front-loaded expense. This guidance is effective for the Company on January 1, 2019. We have evaluated ASU 2016-2 and determined that it will not have a significant impact on our consolidated financial statements.