| N-2 - USD ($) | 3 Months Ended | 12 Months Ended | |||||||||||||||||||||||||||||||||||||||||||||||||
| Dec. 31, 2023 | Sep. 30, 2023 | Jun. 30, 2023 | Mar. 31, 2023 | Dec. 31, 2022 | Sep. 30, 2022 | Jun. 30, 2022 | Mar. 31, 2022 | Dec. 31, 2021 | Sep. 30, 2021 | Jun. 30, 2021 | Mar. 31, 2021 | Dec. 31, 2020 | Sep. 30, 2020 | Jun. 30, 2020 | Mar. 31, 2020 | Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | [7] | Dec. 31, 2014 | [7] | Dec. 31, 2013 | [7] | Dec. 31, 2012 | |||||||||||||||||||||
| Cover [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Entity Central Index Key | 0001478102 | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Amendment Flag | false | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Document Type | N-CSR | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Entity Registrant Name | Western Asset Mortgage Opportunity Fund Inc. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Fee Table [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Shareholder Transaction Expenses [Table Text Block] | Summary of Fund Expenses Record Date Sales Load (as a percentage of offering price) (1) 1.00 % Offering Expenses (as a percentage of offering price) (2) 0.65 % Dividend Reinvestment Plan Fees (3) $ 5.00 (1) Represents the estimated commission with respect to the Common Stock being sold in at-the-market offerings. JonesTrading will be entitled to compensation of up to 1.00% of the gross proceeds of the sale of any Common Stock under the Sales Agreement, with the exact amount of such compensation to be mutually agreed upon in writing by the Fund and JonesTrading from time to time. (2) Costs incurred by the Fund in connection with the shelf offering are recorded as a prepaid expense. These costs are amortized on a pro-rata basis as shares are sold and are presented as a reduction to the net proceeds from sale of shares. Any deferred charges remaining at the end of the life of the shelf offering period will be expensed. (3) Common Stockholders will pay brokerage charges if they direct the Plan Agent to sell Common Stock held in a dividend reinvestment account. There are no fees charged to stockholders for participating in the Fund’s dividend reinvestment plan. However, stockholders participating in the Plan that elect to sell their shares obtained pursuant to the plan would pay $5.00 per transaction to sell shares. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Sales Load [Percent] | [1] | 1% | |||||||||||||||||||||||||||||||||||||||||||||||||
| Dividend Reinvestment and Cash Purchase Fees | [2] | $ 5 | |||||||||||||||||||||||||||||||||||||||||||||||||
| Other Transaction Expenses [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Other Transaction Expenses [Percent] | [3] | 0.65% | |||||||||||||||||||||||||||||||||||||||||||||||||
| Annual Expenses [Table Text Block] | Annual Operating Expenses Percentage of Net Assets Attributable to Common Shares Management Fees (4) 1.71% Interest Payments on Borrowed Funds (5) 5.03% Other Expenses (6) 0.54% Total Annual Fund Operating Expenses 7.28% (4) The Investment Manager receives an annual fee, payable monthly, in an amount equal to 1.00% of the Fund’s average daily Managed Assets. “Managed Assets” means net assets plus the amount of any outstanding borrowings used for leverage and assets attributable to any preferred stock that may be outstanding. If the Fund were to use leverage, the amount of management fees paid to the Investment Manager will be higher than if the Fund does not use leverage because the fees paid are calculated on the Funds Managed Assets. (5) The Fund enters into reverse repurchase agreements. The expenses and rates associated with leverage may vary as and when Borrowings or issuances of Preferred Stock are made. “Interest Payments on Borrowed Funds” reflects an annualized interest charge based on the interest rate and borrowings in effect on December 31, 2023. (6) Expenses based on amounts incurred in the fiscal year ended December 31, 2023. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Management Fees [Percent] | [4] | 1.71% | |||||||||||||||||||||||||||||||||||||||||||||||||
| Interest Expenses on Borrowings [Percent] | [5] | 5.03% | |||||||||||||||||||||||||||||||||||||||||||||||||
| Other Annual Expenses [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Other Annual Expenses [Percent] | [6] | 0.54% | |||||||||||||||||||||||||||||||||||||||||||||||||
| Total Annual Expenses [Percent] | 7.28% | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Expense Example [Table Text Block] | An investor would pay the following expenses on a $1,000 investment in the Fund, assuming a 5% annual return: One Year Three Years Five Years Ten Years $72 $211 $344 $650 | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Expense Example, Year 01 | $ 72 | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Expense Example, Years 1 to 3 | 211 | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Expense Example, Years 1 to 5 | 344 | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Expense Example, Years 1 to 10 | $ 650 | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Purpose of Fee Table , Note [Text Block] | The following additional information is provided for the Fund as of the fiscal year ended December 31, 2023. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Basis of Transaction Fees, Note [Text Block] | [1],[3] | as a percentage of offering price | |||||||||||||||||||||||||||||||||||||||||||||||||
| Other Transaction Fees, Note [Text Block] | Common Stockholders will pay brokerage charges if they direct the Plan Agent to sell Common Stock held in a dividend reinvestment account. There are no fees charged to stockholders for participating in the Fund’s dividend reinvestment plan. However, stockholders participating in the Plan that elect to sell their shares obtained pursuant to the plan would pay $5.00 per transaction to sell shares. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Other Expenses, Note [Text Block] | Expenses based on amounts incurred in the fiscal year ended December 31, 2023. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Management Fee not based on Net Assets, Note [Text Block] | The Investment Manager receives an annual fee, payable monthly, in an amount equal to 1.00% of the Fund’s average daily Managed Assets. “Managed Assets” means net assets plus the amount of any outstanding borrowings used for leverage and assets attributable to any preferred stock that may be outstanding. If the Fund were to use leverage, the amount of management fees paid to the Investment Manager will be higher than if the Fund does not use leverage because the fees paid are calculated on the Funds Managed Assets. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Financial Highlights [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Senior Securities [Table Text Block] | The Fund engaged in senior securities during the prior ten years as follows: Year Ended Total Asset Average Revolving Credit Facility: December 31, 2023* N / N/A N/A December 31, 2022* N/A N/A N/A December 31, 2021* N/A N/A N/A December 31, 2020 $ 45,000,000 $ 4,667 N/A December 31, 2019 $ 98,000,000 $ 3,089 N/A December 31, 2018 $ 99,250,000 $ 3,035 N/A December 31, 2017 $ 101,750,000 $ 3,185 N/A December 31, 2016 $ 101,750,000 $ 3,124 N/A December 31, 2015* $ 80,500,000 $ 3,946 N/A December 31, 2014* $ 116,700,000 $ 3,208 N/A December 31, 2013* $ 116,700,000 $ 3,121 N/A December 31, 2012 $ 30,000,000 $ 9,280 N/A | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Senior Securities Amount | [7] | [7] | [7] | $ 45,000,000 | [7] | [7] | [7] | $ 45,000,000 | $ 98,000,000 | $ 99,250,000 | $ 101,750,000 | $ 101,750,000 | $ 80,500,000 | $ 116,700,000 | $ 116,700,000 | $ 30,000,000 | |||||||||||||||||||||||||||||||||||
| Senior Securities Coverage per Unit | [7] | [7] | [7] | $ 4,667 | [7] | [7] | [7] | $ 4,667 | $ 3,089 | $ 3,035 | $ 3,185 | $ 3,124 | $ 3,946 | $ 3,208 | $ 3,121 | $ 9,280 | |||||||||||||||||||||||||||||||||||
| Senior Securities Average Market Value per Unit | [8] | [7] | [7] | [7] | |||||||||||||||||||||||||||||||||||||||||||||||
| Senior Securities, Note [Text Block] | Senior Securities Table The Fund engaged in senior securities during the prior ten years as follows: Year Ended Total Asset Average Revolving Credit Facility: December 31, 2023* N / N/A N/A December 31, 2022* N/A N/A N/A December 31, 2021* N/A N/A N/A December 31, 2020 $ 45,000,000 $ 4,667 N/A December 31, 2019 $ 98,000,000 $ 3,089 N/A December 31, 2018 $ 99,250,000 $ 3,035 N/A December 31, 2017 $ 101,750,000 $ 3,185 N/A December 31, 2016 $ 101,750,000 $ 3,124 N/A December 31, 2015* $ 80,500,000 $ 3,946 N/A December 31, 2014* $ 116,700,000 $ 3,208 N/A December 31, 2013* $ 116,700,000 $ 3,121 N/A December 31, 2012 $ 30,000,000 $ 9,280 N/A * The Fund had open reverse repurchase agreements at December 31, 2023, 2022, 2021, 2015, 2014 and 2013. ** Not applicable, as these senior securities were not registered for public trading. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Investment Objectives and Practices [Text Block] | Investment Objectives The Fund’s primary investment objective is to provide current income. As a secondary investment objective, the Fund will seek capital appreciation. Principal Investment Policies and Strategies The Fund seeks to achieve its investment objectives by investing primarily in a diverse portfolio of mortgage-backed securities (“MBS”) and mortgage whole loans. Investments in mortgage-backed securities consist primarily of non-agency residential mortgage-backed securities (“RMBS”) and commercial mortgage-backed securities (“CMBS”). The Fund’s investments in mortgage whole loans under normal circumstances will not exceed 20% of its Managed Assets. “Managed Assets” means the net assets of the Fund plus the amount of any Borrowings and assets attributable to Preferred Stock that may be outstanding. A mortgage whole loan is a single mortgage loan issued to a particular borrower and is not securitized. Mortgage whole loans include loans on residential properties such as one to four family dwellings and on commercial properties such as office buildings, shopping centers and other retail properties, hotels and apartment buildings. MBS represent interests in diversified pools of residential or commercial mortgage loans, and typically take the form of pass-through securities or collateralized mortgage obligations (“CMOs”). MBS include, but are not limited to, the following: non-agency RMBS; CMBS; U.S. agency mortgage-backed pass-through securities issued by Government National Mortgage Association, the Federal National Mortgage Association (“Fannie Mae”), the Federal Home Loan Mortgage Corporation (“Freddie Mac”), and other federal agencies, or issues guaranteed by them; delegated underwriting and servicing bonds, including pools of multi-family housing loans issued by Fannie Mae and Freddie Mac; CMOs, including interest only (“IO”), principal only (“PO”) and other mortgage securities backed by U.S. agency or non-agency pass-through securities; mortgage-related asset-backed securities (“ABS”), such as home equity loan-backed securities; MBS credit default swaps (including on the CMBX, TRX and ABX indices) and other derivative instruments related to MBS; inverse floating rate securities, which are derivative interests in MBS; RMBS denominated in currencies other than the U.S. dollar; and repurchase agreements supported by agency MBS; and junior and equity tranches of MBS. The Fund may invest in MBS of any type and of any credit quality, without limitation. The Fund may invest in senior loans, including assignments and participations. Under normal circumstances, the Fund will invest at least 80% of its Managed Assets in MBS and mortgage whole loans. Derivatives counted towards the Fund’s 80% policy are valued based on market value. The Fund also may invest up to 20% of its Managed Assets in other permitted investments, including cash and cash equivalents; Treasury securities; non-mortgage related ABS (such as collateralized bond obligations, collateralized loan obligations and collateralized debt obligations) backed by various asset classes including, but not limited to, small balance commercial mortgages, aircrafts, automobiles, credit cards, equipment, manufactured housing, franchises, recreational vehicles and student loans; and investment grade and below investment grade fixed income securities including bonds, debentures, notes, commercial paper and other similar types of debt instruments including hybrid securities. The Fund also may invest in any newly developed mortgage-related derivatives that may hereafter become available for mortgage investing. The Fund may invest in derivative instruments, such as options contracts, futures contracts, options on futures contracts, indexed securities, credit linked notes, credit default swaps and other swap agreements for investment, hedging and risk management purposes; provided that the Fund’s use of derivative instruments, as measured by the total notional amount of all such instruments, will not exceed 20% of its Managed Assets. With respect to this limitation, the Fund may net derivatives with opposite exposure to the same underlying instrument. Notwithstanding the foregoing, the Fund may invest without limitation in Treasury futures, Eurodollar futures, interest rate swaps, swaptions or similar instruments and combinations thereof. To the extent that the security or index underlying the derivative or synthetic instrument is or is composed of MBS, the Fund will include such derivative and synthetic instruments for the purposes of the Fund’s policy to invest at least 80% of its Managed Assets in MBS and mortgage whole loans. The Fund may sell certain equities or fixed income securities short including, but not limited to, Treasury securities, for investing or hedging purposes. The Fund may invest in debt investments of any maturity and duration. The Fund may invest a substantial portion of its assets in MBS that were originally rated AAA, but subsequently have been downgraded to below investment grade. The Fund is not limited in its ability to invest in below investment grade or illiquid securities. Below investment grade fixed income securities are rated below “BBB-” by Standard & Poor’s Ratings Services, a division of The McGraw Hill Companies, Inc. or Fitch Ratings, Inc., below “Baa3” by Moody’s Investors Service, Inc. or comparably rated by another nationally recognized statistical rating organization (“NRSRO”) or, if unrated, determined by Western Asset to be of comparable quality. Below investment grade fixed income securities are commonly referred to as “high yield” or “junk” securities and are regarded as having predominantly speculative characteristics with respect to the issuer’s capacity to pay interest and repay principal. In the event that a security receives different ratings from different NRSROs, the Fund will treat the security as being rated in the highest rating category received from an NRSRO. “Illiquid securities” are securities which cannot be sold within seven days in the ordinary course of business at approximately the value at which the Fund has valued the securities. Western Asset does not rely solely on credit ratings, and develops its own analysis of issuer credit quality. The Fund may purchase unrated securities if Western Asset determines that the securities are of comparable quality to rated securities that the Fund may purchase. Summary of information regarding the Fund (unaudited) (cont’d) The Fund may enter into repurchase agreements, in which the Fund purchases a security from a bank or broker-dealer and the bank or broker-dealer agrees to repurchase the security at the Fund’s cost plus interest within a specified time. The Fund may enter into reverse repurchase agreements, under which the Fund will effectively pledge its assets as collateral to secure a short-term loan. The Fund may use leverage through borrowings, including loans from certain financial institutions and/or the issuance of debt securities, and through the issuance of preferred stock. The Fund may use leverage through borrowings in an aggregate amount of up to approximately 33 1/3% of the Fund’s total assets less all liabilities and indebtedness not represented by senior securities (for these purposes, “total net assets”) immediately after such borrowings. Furthermore, the Fund may use leverage through the issuance of preferred stock in an aggregate amount of liquidation preference attributable to the preferred stock combined with the aggregate amount of any borrowings of up to approximately 33 1/3% of the Fund’s total net assets immediately after such issuance. In addition, the Fund may enter into additional reverse repurchase agreements and/or use similar investment management techniques that may provide leverage, but which are not subject to the foregoing 33 1/3% limitation so long as the Fund has covered its commitment with respect to such techniques by segregating liquid assets, entering into offsetting transactions or owning positions covering related obligations. The Fund may purchase securities on a when-issued or delayed delivery basis. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk Factors [Table Text Block] | Principal Risk Factors The Fund is a non-diversified, closed-end management investment company designed primarily as a long-term investment and not as a trading vehicle. The Fund is not intended to be a complete investment program and, due to the uncertainty inherent in all investments, there can be no assurance that the Fund will achieve its investment objectives. The Fund’s performance and the value of its investments will vary in response to changes in interest rates, inflation, the financial condition of a security’s issuer, ratings on a security and other market factors. Your securities at any point in time may be worth less than you invested, even after taking into account the reinvestment of Fund dividends and distributions. Below are the principal risks associated with an investment in the Fund. Investment Risk and Market Risk. Market Price Discount from Net Asset Value. from the risk that the Fund’s net asset value could decrease as a result of its investment activities and may be a greater risk to investors expecting to sell their Common Stock in a relatively short period following completion of this offering. Whether investors will realize gains or losses upon the sale of the Common Stock will depend not upon the Fund’s net asset value but upon whether the market price of the Common Stock at the time of sale is above or below the investor’s purchase price for the Common Stock. Risks Related to Investments in MBS. The risks associated with MBS include: (1) credit risk associated with the performance of the underlying mortgage properties and of the borrowers owning these properties; (2) adverse changes in economic conditions and circumstances, which are more likely to have an adverse impact on MBS secured by loans on certain types of commercial properties than on those secured by loans on residential properties; (3) prepayment risk, which can lead to significant fluctuations in value of the MBS; (4) loss of all or part of the premium, if any, paid; and (5) decline in the market value of the security, whether resulting from changes in interest rates, prepayments on the underlying mortgage collateral or perceptions of the credit risk associated with the underlying mortgage collateral. MBS represent an interest in a pool of mortgages. When market interest rates decline, more mortgages are refinanced and the securities are paid off earlier than expected. Prepayments may also occur on a scheduled basis or due to foreclosure. When market interest rates increase, the market values of MBS decline. At the same time, however, mortgage refinancings and prepayments slow, lengthening the effective maturities of these securities. As a result, the negative effect of the rate increase on the market value of MBS is usually more pronounced than it is for other types of debt securities. In addition, due to Summary of information regarding the Fund (unaudited) (cont’d) increased instability in the credit markets, the market for some MBS has experienced reduced liquidity and greater volatility with respect to the value of such securities, making it more difficult to value such securities. Moreover, the relationship between borrower prepayments and changes in interest rates may mean some high-yielding mortgage-related and asset-backed securities have less potential for increases in value if market interest rates were to fall than conventional bonds with comparable maturities. In addition, in periods of falling interest rates, the rate of prepayments tends to increase. During such periods, the reinvestment of prepayment proceeds by the Fund will generally be at lower rates than the rates that were carried by the obligations that have been prepaid. Because of these and other reasons, mortgage-related and asset-backed security’s total return and maturity may be difficult to predict precisely. To the extent that the Fund purchases mortgage-related securities at a premium, prepayments (which may be made without penalty) may result in loss of the Fund’s principal investment to the extent of premium paid. The Fund’s success depends on the Western Asset’s ability to analyze the relationship of changing interest rates on prepayments of the mortgage loans that underlie the Fund’s MBS. Changes in interest rates and prepayments affect the market price of the target assets that the Fund intends to purchase and any target assets that the Fund holds at a given time. As part of the Fund’s overall portfolio risk management, Western Asset will analyze interest rate changes and prepayment trends separately and collectively to assess their effects on the Fund’s investment portfolio. In conducting its analysis, Western Asset will depend on certain assumptions based upon historical trends with respect to the relationship between interest rates and prepayments under normal market conditions. If the recent dislocations in the mortgage market or other developments change the way that prepayment trends have historically responded to interest rate changes, Western Asset’s ability to (1) assess the market value of the Fund’s investment portfolio, (2) implement any hedging strategies and (3) implement techniques to reduce prepayment rate volatility would be significantly affected, which could materially adversely affect the Fund’s financial position and results of operations. In general, losses on a mortgaged property securing a mortgage loan included in a securitization will be borne first by the equity holder of the property, then by a cash reserve fund or letter of credit, if any, then by the holder of a mezzanine loan or B-Note, if any, then by the “first loss” subordinated security holder (generally, the “B-Piece” buyer) and then by the holder of a higher-rated security. In the event of default and the exhaustion of any equity support, reserve fund, letter of credit, mezzanine loans or B-Notes, and any classes of securities junior to those in which the Fund invests, the Fund will not be able to recover all of its investment in the MBS it purchases. MBS in which the Fund invests may not contain reserve funds, letters of credit, mezzanine loans and/or junior classes of securities. The prices of lower credit quality securities are generally less sensitive to interest rate changes than more highly rated investments, but more sensitive to adverse economic downturns or individual issuer developments. MBS generally are classified as either CMBS or RMBS, each of which are subject to certain specific risks as further described below. See “—Non-Agency RMBS Risk” and “—CMBS Risk.” Non-Agency RMBS Risk. Credit-Related Risk Associated with Borrowers on Non-Agency RMBS. Impact of Real Estate and Mortgage Loan Markets on Non-Agency RMBS. Summary of information regarding the Fund (unaudited) (cont’d) properties. At any one time, a portfolio of non-agency RMBS may be backed by residential mortgage loans that are highly concentrated in only a few states or regions. As a result, the performance of such residential mortgage loans may be more susceptible to a downturn in the economy, including in particular industries that are highly represented in such states or regions, natural calamities and other adverse conditions affecting such areas. In addition, the residential mortgage loans underlying non-agency RMBS may include so-called “jumbo” residential mortgage loans, having original principal balances that are significantly higher than is generally the case for residential mortgage loans. If the portfolio of residential mortgage loans underlying a non-agency RMBS includes a high concentration of “jumbo” residential mortgage loans, the performance of the non-agency RMBS will be more susceptible to the performance of individual borrowers and adverse economic conditions in general than would otherwise be the case. Another factor that may contribute to, and may in the future result in, higher delinquency and default rates is the increase in monthly payments on adjustable-rate mortgage loans. Any increase in prevailing market interest rates may result in increased payments for borrowers who have adjustable-rate mortgage loans. Moreover, with respect to hybrid mortgage loans after their initial fixed-rate period or other so-called adjustable-rate mortgage loans, interest-only products or products having a lower rate, and with respect to mortgage loans with a negative amortization feature which reach their negative amortization cap, borrowers may experience a substantial increase in their monthly payment even without an increase in prevailing market interest rates. Increases in payments for borrowers may result in increased rates of delinquencies and defaults on residential mortgage loans underlying the non-agency RMBS. The past performance of the market for non-agency RMBS is not a reliable indicator of future performance because of the unprecedented and unpredictable performance of the residential mortgage loan market. As a result of rising concerns about increases in delinquencies and defaults on residential mortgage loans (particularly on subprime and adjustable-rate mortgage loans) and as a result of increasing concerns about the financial strength of originators and servicers and their ability to perform their obligations with respect to non-agency RMBS, there may be an adverse change in the market sentiments of investors about the market values and volatility and the degree of risk of non-agency RMBS generally. Some or all of the underlying residential mortgage loans in an issue of non-agency RMBS may have balloon payments due on their respective maturity dates. Balloon residential mortgage loans involve a greater risk to a lender than fully amortizing loans, because the ability of a borrower to pay such amount will normally depend on its ability to obtain refinancing of the related mortgage loan or sell the related mortgaged property at a price sufficient to permit the borrower to make the balloon payment, which will depend on a number of factors prevailing at the time such refinancing or sale is required, including, without limitation, the strength of the local or national residential real estate markets, interest rates and general economic conditions and the financial condition of the borrower. If borrowers are unable to make such balloon payments, the related issue of non-agency RMBS may experience losses. Prepayment Risk Associated with Non-Agency RMBS Non-agency RMBS typically contain provisions that require repurchase of mortgage loans by the originator or other seller in the event of a breach of a representation or warranty regarding loan quality and characteristics of such loan. Any repurchase of a mortgage loan as a result of a breach has the same effect on the yield received on the related issue of non-agency RMBS as a prepayment of such mortgage loan. Any increase in breaches of representations and the consequent repurchases of mortgage loans that result from inadequate underwriting procedures and policies and protections against fraud will have the same effect on the yield on the related non-agency RMBS as an increase in prepayment rates. CMBS are also subject to prepayment risk, as described above. Risk of prepayment may be reduced for commercial real estate property loans containing significant prepayment penalties or prohibitions on principal payments for a period of time following origination. The Fund may also invest in MBS which are IO securities and PO securities. An IO security receives some or all of the interest portion of the underlying collateral and little or no principal. A reference principal value called a notional value is used to calculate the amount Summary of information regarding the Fund (unaudited) (cont’d) of interest due. IO securities are sold at a deep discount to their notional principal amount. A PO security does not receive any interest, is priced at a deep discount to its redemption value and ultimately receives the redemption value. Generally speaking, when interest rates are falling and prepayment rates are increasing, the value of a PO security will rise and the value of an IO security will fall. Conversely, when interest rates are rising and prepayment rates are decreasing, generally the value of a PO security will fall and the value of an IO security will rise. Legal Risks Associated with Non-Agency RMBS. Notwithstanding these protections, an issuer of non-agency RMBS may be exposed to an unquantifiable amount of potential assignee liability because, first, the amount of potential assignee liability under certain predatory lending laws is unclear and has yet to be litigated, and, second, in the event a predatory lending law does not prohibit class action lawsuits, it is possible that an issuer of non-agency RMBS could be liable in damages for more than the original principal amount of the offending loans held by it. In such circumstances the issuer of non-agency RMBS may be forced to seek contribution from other parties, who may no longer exist or have adequate funds available to fund such contribution. In addition, structural and legal risks of non-agency RMBS include the possibility that, in a bankruptcy or similar proceeding involving the originator or the servicer (often the same entity or affiliates), the assets of the issuer could be treated as never having been truly sold by the originator to the issuer and could be substantively consolidated with those of the originator, or the transfer of such assets to the issuer could be voided as a fraudulent transfer. Challenges based on such doctrines could result also in cash flow delays and losses on the related issue of non-agency RMBS. In some cases, servicers of non-agency RMBS have been the subject of legal proceedings involving the origination and/or servicing practices of such servicers. Large groups of private litigants and states attorneys general have brought such proceedings. Because of the large volume of mortgage loans originated and serviced by such servicers, such litigation can cause heightened financial strain on servicers. In other cases, origination and servicing practices may cause or contribute to such strain, because of representation and warranty repurchase liability arising in MBS and mortgage loan sale transactions. Any such financial strain could cause servicers to service below required standards, causing delinquencies and losses in any related MBS transaction to rise, and in extreme cases could cause the servicer to seek the protection of any applicable bankruptcy or insolvency law. In any such proceeding, it is unclear whether the fees that the servicer charges in such transactions would be sufficient to permit that servicer or a successor servicer to service the mortgage loans in such transaction adequately. If such fees had to be increased, it is likely that the most subordinated security holders in such transactions would be effectively required to pay such increased fees. Finally, these entities may be the subject of future laws designed to protect consumers from defaulting on their mortgage loans. Such laws may have an adverse effect on the cash flows paid under such non-agency RMBS. In the past year, a number of lenders specializing in residential mortgages have sought bankruptcy protection, shut down or been refused further financings from their lenders. In addition, certain lenders who service and/or issue non-agency RMBS have announced that they are being investigated by or have received information requests from U.S. federal and/or state authorities, including the Securities and Exchange Commission. As a result of such investigations and other similar investigations and general concerns about the adequacy or accuracy of disclosure of risks to borrowers and their understanding of such risks, U.S. financial regulators have indicated that they may propose new guidelines for the mortgage industry. Guidelines, if introduced, together with the other factors described herein, may make it more difficult for borrowers with weaker credit to refinance, which may lead to further increases in delinquencies, extensions in duration and losses in mortgage-related assets. Furthermore, because some mortgage loans have high recoveries, and as Summary of information regarding the Fund (unaudited) (cont’d) property values decline, increasing loan-to-value ratios, recoveries on some defaulted mortgage loans are more likely to be less than the amounts owed under such mortgage loans, resulting in higher net losses than would have been the case had property values remained the same or increased. CMBS Risk. The exercise of remedies and successful realization of liquidation proceeds relating to CMBS is also highly dependent on the performance of the servicer or special servicer. In many cases, overall control over the special servicing of related underlying mortgage loans will be held by a “directing certificateholder” or a “controlling class representative,” which is appointed by the holders of the most subordinate class of CMBS in such series. The Fund may not have the right to appoint the directing certificateholder. In connection with the servicing of the specially serviced mortgage loans, the related special servicer may, at the direction of the directing certificateholder, take actions with respect to the specially serviced mortgage loans that could adversely affect the Fund’s interests. There may be a limited number of special servicers available, particularly those that do not have conflicts of interest. Western Asset will value the Fund’s potential CMBS investments based on loss-adjusted yields, taking into account estimated future losses on the mortgage loans included in the securitization’s pool of loans, and the estimated impact of these losses on expected future cash flows. Western Asset’s loss estimates may not prove accurate, as actual results may vary from estimates. In the event that Western Asset overestimates the pool level losses relative to the price the Fund pays for a particular CMBS investment, the Fund may experience losses with respect to such investment. Interest Rate Risk Associated with Non-Agency RMBS and CMBS. The value of fixed rate debt securities can be expected to vary inversely with changes in prevailing interest rates. Fixed rate debt securities with longer maturities, which tend to produce higher yields, are subject to potentially greater capital appreciation and depreciation than securities with shorter maturities. Structural Risks Associated with Non-Agency RMBS and CMBS Summary of information regarding the Fund (unaudited) (cont’d) Subordination Risk Associated with Non-Agency RMBS and CMBS. Credit Risk and Counterparty Risk. Interest Rate Risk Leverage Risk. its obligations created by the use of leverage or derivatives. The use of leverage is considered to be a speculative investment practice and may result in the loss of a substantial amount, and possibly all, of the fund’s assets. In addition, the fund’s portfolio will be leveraged if it exercises its right to delay payment on a redemption, and losses will result if the value of the fund’s assets declines between the time a redemption request is deemed to be received by the fund and the time the fund liquidates assets to meet redemption requests. ABS Risk. Below Investment Grade (“High Yield” or “Junk”) Securities Risk. Summary of information regarding the Fund (unaudited) (cont’d) susceptible to adverse events, credit downgrades and negative sentiments and may be difficult to sell at a desired price, or at all, during periods of uncertainty or market turmoil. Distressed Investments. The Fund intends to invest in distressed investments including non-performing and sub-performing RMBS and CMBS, many of which are not publicly traded and which may involve a substantial degree of risk. In certain periods, there may be little or no liquidity in the markets for these securities or instruments. In addition, the prices of such securities or instruments may be subject to periods of abrupt and erratic market movements and above-average price volatility. It may be more difficult to value such securities and the spread between the bid and asked prices of such securities may be greater than normally expected. If the Western Asset’s evaluation of the risks and anticipated outcome of an investment in a distressed security should prove incorrect, the Fund may lose a substantial portion or all of its investment. Furthermore, investments in assets operating in workout modes or under Chapter 11 of the United States Bankruptcy Code, as amended, and other comparable bankruptcy laws may, in certain circumstances, be subject to certain additional potential liabilities that may exceed the value of the Fund’s original investment. For example, under certain circumstances, lenders who have inappropriately exercised control of the management and policies of a debtor may have their claims subordinated or disallowed or counterclaims may be filed and lenders may be found liable for damages suffered by various parties as a result of such actions. In addition, under certain circumstances, payments to the Fund and distributions by the Fund to its investors may be reclaimed if any such payment or distribution is later determined to have been a fraudulent conveyance or a preferential payment. The Fund is not limited in its ability to invest in distressed investments. Credit Risk Associated with Originators and Servicers of Residential and Commercial Mortgage Loans. borrowers, decreased originations by such originators of mortgage loans and increased delinquencies and defaults on such mortgage loans, as well as from increases in claims for repurchases of mortgage loans previously sold by them under agreements that require repurchase in the event of breaches of representations regarding loan quality and characteristics. Such difficulties may affect the performance of non-agency RMBS and CMBS backed by mortgage loans. Furthermore, the inability of the originator to repurchase such mortgage loans in the event of loan representation breaches or the servicer to repurchase such mortgage loans upon a breach of its servicing obligations also may affect the performance of related non-agency RMBS and CMBS. Delinquencies and losses on, and, in some cases, claims for repurchase by the originator of, mortgage loans originated by some mortgage lenders have increased as a result of inadequate underwriting procedures and policies, including inadequate due diligence, failure to comply with predatory and other lending laws and, particularly in the case of any “no documentation” or “limited documentation” mortgage loans that may support non-agency RMBS, inadequate verification of income and employment history. Delinquencies and losses on, and claims for repurchase of, mortgage loans originated by some mortgage lenders have also resulted from fraudulent activities of borrowers, lenders, appraisers, and other residential mortgage industry participants such as mortgage brokers, including misstatements of income and employment history, identity theft and overstatements of the appraised value of mortgaged properties. Many of these originators and servicers are very highly leveraged. These difficulties may also increase the chances that these entities may default on their warehousing or other credit lines or become insolvent or bankrupt and thereby increase the likelihood that repurchase obligations will not be fulfilled and the potential for loss to holders of non-agency RMBS, CMBS and subordinated security holders. The servicers of non-agency RMBS and CMBS are often the same entities as, or affiliates of, the originators of these mortgage loans. Accordingly, the financial risks relating to originators of non-agency RMBS and CMBS described immediately above also may affect the servicing of non-agency RMBS and CMBS. In the case of such servicers, and other servicers, financial difficulties may have a negative effect on the ability of servicers to pursue collection on mortgage loans that are experiencing increased delinquencies and defaults and to maximize recoveries on sale of underlying properties following foreclosure. Non-agency RMBS and CMBS typically provide that the servicer is required to make advances in respect of delinquent mortgage loans. However, servicers experiencing financial difficulties may not be able to perform these obligations or obligations that they may have to other parties of transactions involving these securities. Like originators, these entities are typically very highly leveraged. Such difficulties may cause servicers to default under their financing arrangements. In certain cases, such entities may be forced to seek bankruptcy protection. Due to the application of the provisions of bankruptcy law, servicers who have sought bankruptcy protection may not be required to advance such amounts. Even Summary of information regarding the Fund (unaudited) (cont’d) if a servicer were able to advance amounts in respect of delinquent mortgage loans, its obligation to make such advances may be limited to the extent that it does not expect to recover such advances due to the deteriorating credit of the delinquent mortgage loans or declining value of the related mortgaged properties. Moreover, servicers may overadvance against a particular mortgage loan or charge too many costs of resolution or foreclosure of a mortgage loan to a securitization, which could increase the potential losses to holders of non-agency RMBS and CMBS. In such transactions, a servicer’s obligation to make such advances may also be limited to the amount of its servicing fee. In addition, if an issue of non-agency RMBS and CMBS provides for interest on advances made by the servicer, in the event that foreclosure proceeds or payments by borrowers are not sufficient to cover such interest, such interest will be paid to the servicer from available collections or other mortgage income, thereby reducing distributions made on the non-agency RMBS and CMBS and, in the case of senior-subordinated non-agency RMBS and CMBS described below, first from distributions that would otherwise be made on the most subordinated non-agency RMBS and CMBS of such issue. Any such financial difficulties may increase the possibility of a servicer termination and the need for a transfer of servicing and any such liabilities or inability to assess such liabilities may increase the difficulties and costs in affecting such transfer and the potential loss, through the allocation of such increased cost of such transfer, to subordinated security holders. There can be no assurance that originators and servicers of mortgage loans will not continue to experience serious financial difficulties or experience such difficulties in the future, including becoming subject to bankruptcy or insolvency proceedings, or that underwriting procedures and policies and protections against fraud will be sufficient in the future to prevent such financial difficulties or significant levels of default or delinquency on mortgage loans. Because the recent financial difficulties experienced by such originators and services is unprecedented and unpredictable, the past performance of the residential and commercial mortgage loans originated and serviced by them (and the corresponding performance of the related non-agency RMBS and CMBS) is not a reliable indicator of the future performance of such residential mortgage loans (or the related non-agency RMBS and CMBS). Subprime Mortgage Market Risk. rates. Also, a number of residential mortgage loan originators have experienced serious financial difficulties or bankruptcy. Largely due to the foregoing, reduced investor demand for mortgage loans and mortgage-related securities and increased investor yield requirements have caused limited liquidity in the secondary market for mortgage-related securities, which can adversely affect the market value of mortgage-related securities. It is possible that such limited liquidity in such secondary markets could continue or worsen. The Fund may acquire non-agency RMBS backed by collateral pools of mortgage loans that have been originated using underwriting standards that are less restrictive than those used in underwriting “prime mortgage loans” and “Alt-A mortgage loans.” These lower standards include mortgage loans made to borrowers having imperfect or impaired credit histories, mortgage loans where the amount of the loan at origination is 80% or more of the value of the mortgage property, mortgage loans made to borrowers with low credit scores, mortgage loans made to borrowers who have other debt that represents a large portion of their income and mortgage loans made to borrowers whose income is not required to be disclosed or verified. Due to economic conditions, including increased interest rates and lower home prices, as well as aggressive lending practices, subprime mortgage loans have in recent periods experienced increased rates of delinquency, foreclosure, bankruptcy and loss, and they are likely to continue to experience delinquency, foreclosure, bankruptcy and loss rates that are higher, and that may be substantially higher, than those experienced by mortgage loans underwritten in a more traditional manner. Thus, because of the higher delinquency rates and losses associated with subprime mortgage loans, the performance of non-agency RMBS backed by subprime mortgage loans that the Fund may acquire could be correspondingly adversely affected, which could adversely impact the Fund’s results of operations, financial condition and business. If the economy of the United States further deteriorates, the incidence of mortgage foreclosures, especially subprime mortgages, may continue to increase, which may adversely affect the value of any MBS owned by the Fund. The U.S. Congress and various government regulatory authorities have discussed the possibility of restructuring mortgages and imposing forbearance requirements on defaulted mortgages. Neither LMPFA nor Western Asset can predict the form any such modifications, forbearance or related regulations might take, and these regulations may adversely affect the value of MBS owned by the Fund. Risks Relating to Investments in Mortgage Whole Loans. Credit Risk Associated With Investments in Mortgage Whole Loans. Summary of information regarding the Fund (unaudited) (cont’d) federal agency or any federally chartered corporation. As a result, a mortgage whole loan is directly exposed to losses resulting from default and foreclosure. Therefore, the value of the underlying property, the creditworthiness and financial position of the borrower, and the priority and enforceability of the lien are each of great importance. Whether or not Legg Mason, Western Asset or their affiliates have participated in the negotiation of the terms of any such mortgages, there can be no assurance as to the adequacy of the protection of the terms of the loan, including the validity or enforceability of the loan and the maintenance of the anticipated priority and perfection of the applicable security interests. Furthermore, claims may be asserted that might interfere with enforcement of the rights of the Fund. In the event of a foreclosure, the Fund may assume direct ownership of the underlying real estate. The liquidation proceeds upon sale of such real estate may not be sufficient to recover the Fund’s cost basis in the loan, resulting in a loss to the Fund. Any costs or delays involved in the effectuation of a foreclosure of the loan or a liquidation of the underlying property will further reduce the proceeds and thus increase the loss. Higher-than-expected rates of default and/or higher-than-expected loss severities on these investments could adversely affect the value of these assets. Accordingly, defaults in the payment of principal and/or interest on the Fund’s residential and commercial whole loans would likely result in the Fund incurring losses of income from, and/or losses in market value relating to, these assets, which could materially adversely affect the Fund’s results of operations. Holders of residential and commercial whole loans are subject to the risk that the related borrowers may default or have defaulted on their obligations to make full and timely payments of principal and interest. A number of factors impact a borrower’s ability to repay including, among other things, changes in employment status, changes in interest rates or the availability of credit, and changes in real estate values. In addition to the credit risk associated with these assets, residential and commercial whole loans are less liquid than certain of the Fund’s other credit sensitive assets, which may make them more difficu | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Share Price [Table Text Block] | Market Price and Net Asset Valuation (NAV) Information The Fund’s Common Stock is traded on the NYSE under the symbol “DMO”. The below table details for the period indicated the high and low closing market prices and NAV as well as the high and low of the premium and discount of the market value compared to the NAV. Quarterly Closing Sale Price Quarter-End Closing High Low Sale Price Net Asset (1) Premium/ of Quarter- Sale Price (2) Fiscal Year 2023: March 31, 2023 $11.51 $10.25 $10.45 $12.16 (14.06) % June 30, 2023 $10.80 $10.17 $10.58 $12.02 (11.98) % September 30, 2023 $11.25 $10.32 $10.71 $11.96 (10.45) % December 31, 2023 $11.24 $10.11 $11.17 $12.05 (7.30) % Fiscal Year 2022: March 31, 2022 $15.52 $13.09 $13.37 $14.30 (6.50) % June 30, 2022 $13.45 $11.40 $11.68 $13.24 (11.78) % September 30, 2022 $12.84 $10.95 $11.11 $12.75 (12.86) % December 31, 2022 $11.48 $10.47 $10.77 $12.12 (11.14) % Fiscal Year 2021: March 31, 2021 $14.96 $14.02 $14.64 $14.92 (1.88) % June 30, 2021 $15.64 $14.67 $15.59 $15.08 3.38 % September 30, 2021 $16.24 $15.33 $15.46 $15.43 0.19 % December 31, 2021 $16.13 $15.09 $15.21 $15.40 (1.23) % Fiscal Year 2020: March 31, 2020 $21.38 $11.83 $12.80 $12.47 2.65 % June 30, 2020 $14.71 $10.86 $14.67 $14.08 4.19 % September 30, 2020 $14.98 $12.54 $13.12 $14.25 (7.93) % December 31, 2020 $14.41 $12.76 $14.18 $14.96 (5.21) % 61 Source of market prices: Bloomberg. (1) NAV per share is determined as of close of business on the last day of the relevant quarter and therefore may not reflect the NAV per share on the date of the high and low closing sales prices, which may or may not fall on the last day of the quarter. (2) Calculated as of the quarter-end closing sales price divided by the quarter-end NAV. The NAV per Common Share on December 31, 2023 was $12.05 and the market price per Common Stock at the close of business on December 31, 2023 was $11.17, representing a (7.30)% discount from such net asset value. As of December 31, 2023, the Fund has 11,383,541 outstanding shares of Common Stock. | ||||||||||||||||||||||||||||||||||||||||||||||||||
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| Risk [Text Block] | Investment Risk and Market Risk. | ||||||||||||||||||||||||||||||||||||||||||||||||||
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| Risk [Text Block] | Market Price Discount from Net Asset Value. from the risk that the Fund’s net asset value could decrease as a result of its investment activities and may be a greater risk to investors expecting to sell their Common Stock in a relatively short period following completion of this offering. Whether investors will realize gains or losses upon the sale of the Common Stock will depend not upon the Fund’s net asset value but upon whether the market price of the Common Stock at the time of sale is above or below the investor’s purchase price for the Common Stock. | ||||||||||||||||||||||||||||||||||||||||||||||||||
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| Risk [Text Block] | Risks Related to Investments in MBS. The risks associated with MBS include: (1) credit risk associated with the performance of the underlying mortgage properties and of the borrowers owning these properties; (2) adverse changes in economic conditions and circumstances, which are more likely to have an adverse impact on MBS secured by loans on certain types of commercial properties than on those secured by loans on residential properties; (3) prepayment risk, which can lead to significant fluctuations in value of the MBS; (4) loss of all or part of the premium, if any, paid; and (5) decline in the market value of the security, whether resulting from changes in interest rates, prepayments on the underlying mortgage collateral or perceptions of the credit risk associated with the underlying mortgage collateral. MBS represent an interest in a pool of mortgages. When market interest rates decline, more mortgages are refinanced and the securities are paid off earlier than expected. Prepayments may also occur on a scheduled basis or due to foreclosure. When market interest rates increase, the market values of MBS decline. At the same time, however, mortgage refinancings and prepayments slow, lengthening the effective maturities of these securities. As a result, the negative effect of the rate increase on the market value of MBS is usually more pronounced than it is for other types of debt securities. In addition, due to Summary of information regarding the Fund (unaudited) (cont’d) increased instability in the credit markets, the market for some MBS has experienced reduced liquidity and greater volatility with respect to the value of such securities, making it more difficult to value such securities. Moreover, the relationship between borrower prepayments and changes in interest rates may mean some high-yielding mortgage-related and asset-backed securities have less potential for increases in value if market interest rates were to fall than conventional bonds with comparable maturities. In addition, in periods of falling interest rates, the rate of prepayments tends to increase. During such periods, the reinvestment of prepayment proceeds by the Fund will generally be at lower rates than the rates that were carried by the obligations that have been prepaid. Because of these and other reasons, mortgage-related and asset-backed security’s total return and maturity may be difficult to predict precisely. To the extent that the Fund purchases mortgage-related securities at a premium, prepayments (which may be made without penalty) may result in loss of the Fund’s principal investment to the extent of premium paid. The Fund’s success depends on the Western Asset’s ability to analyze the relationship of changing interest rates on prepayments of the mortgage loans that underlie the Fund’s MBS. Changes in interest rates and prepayments affect the market price of the target assets that the Fund intends to purchase and any target assets that the Fund holds at a given time. As part of the Fund’s overall portfolio risk management, Western Asset will analyze interest rate changes and prepayment trends separately and collectively to assess their effects on the Fund’s investment portfolio. In conducting its analysis, Western Asset will depend on certain assumptions based upon historical trends with respect to the relationship between interest rates and prepayments under normal market conditions. If the recent dislocations in the mortgage market or other developments change the way that prepayment trends have historically responded to interest rate changes, Western Asset’s ability to (1) assess the market value of the Fund’s investment portfolio, (2) implement any hedging strategies and (3) implement techniques to reduce prepayment rate volatility would be significantly affected, which could materially adversely affect the Fund’s financial position and results of operations. In general, losses on a mortgaged property securing a mortgage loan included in a securitization will be borne first by the equity holder of the property, then by a cash reserve fund or letter of credit, if any, then by the holder of a mezzanine loan or B-Note, if any, then by the “first loss” subordinated security holder (generally, the “B-Piece” buyer) and then by the holder of a higher-rated security. In the event of default and the exhaustion of any equity support, reserve fund, letter of credit, mezzanine loans or B-Notes, and any classes of securities junior to those in which the Fund invests, the Fund will not be able to recover all of its investment in the MBS it purchases. MBS in which the Fund invests may not contain reserve funds, letters of credit, mezzanine loans and/or junior classes of securities. The prices of lower credit quality securities are generally less sensitive to interest rate changes than more highly rated investments, but more sensitive to adverse economic downturns or individual issuer developments. MBS generally are classified as either CMBS or RMBS, each of which are subject to certain specific risks as further described below. See “—Non-Agency RMBS Risk” and “—CMBS Risk.” | ||||||||||||||||||||||||||||||||||||||||||||||||||
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| Risk [Text Block] | Non-Agency RMBS Risk. Credit-Related Risk Associated with Borrowers on Non-Agency RMBS. Impact of Real Estate and Mortgage Loan Markets on Non-Agency RMBS. Summary of information regarding the Fund (unaudited) (cont’d) properties. At any one time, a portfolio of non-agency RMBS may be backed by residential mortgage loans that are highly concentrated in only a few states or regions. As a result, the performance of such residential mortgage loans may be more susceptible to a downturn in the economy, including in particular industries that are highly represented in such states or regions, natural calamities and other adverse conditions affecting such areas. In addition, the residential mortgage loans underlying non-agency RMBS may include so-called “jumbo” residential mortgage loans, having original principal balances that are significantly higher than is generally the case for residential mortgage loans. If the portfolio of residential mortgage loans underlying a non-agency RMBS includes a high concentration of “jumbo” residential mortgage loans, the performance of the non-agency RMBS will be more susceptible to the performance of individual borrowers and adverse economic conditions in general than would otherwise be the case. Another factor that may contribute to, and may in the future result in, higher delinquency and default rates is the increase in monthly payments on adjustable-rate mortgage loans. Any increase in prevailing market interest rates may result in increased payments for borrowers who have adjustable-rate mortgage loans. Moreover, with respect to hybrid mortgage loans after their initial fixed-rate period or other so-called adjustable-rate mortgage loans, interest-only products or products having a lower rate, and with respect to mortgage loans with a negative amortization feature which reach their negative amortization cap, borrowers may experience a substantial increase in their monthly payment even without an increase in prevailing market interest rates. Increases in payments for borrowers may result in increased rates of delinquencies and defaults on residential mortgage loans underlying the non-agency RMBS. The past performance of the market for non-agency RMBS is not a reliable indicator of future performance because of the unprecedented and unpredictable performance of the residential mortgage loan market. As a result of rising concerns about increases in delinquencies and defaults on residential mortgage loans (particularly on subprime and adjustable-rate mortgage loans) and as a result of increasing concerns about the financial strength of originators and servicers and their ability to perform their obligations with respect to non-agency RMBS, there may be an adverse change in the market sentiments of investors about the market values and volatility and the degree of risk of non-agency RMBS generally. Some or all of the underlying residential mortgage loans in an issue of non-agency RMBS may have balloon payments due on their respective maturity dates. Balloon residential mortgage loans involve a greater risk to a lender than fully amortizing loans, because the ability of a borrower to pay such amount will normally depend on its ability to obtain refinancing of the related mortgage loan or sell the related mortgaged property at a price sufficient to permit the borrower to make the balloon payment, which will depend on a number of factors prevailing at the time such refinancing or sale is required, including, without limitation, the strength of the local or national residential real estate markets, interest rates and general economic conditions and the financial condition of the borrower. If borrowers are unable to make such balloon payments, the related issue of non-agency RMBS may experience losses. Prepayment Risk Associated with Non-Agency RMBS Non-agency RMBS typically contain provisions that require repurchase of mortgage loans by the originator or other seller in the event of a breach of a representation or warranty regarding loan quality and characteristics of such loan. Any repurchase of a mortgage loan as a result of a breach has the same effect on the yield received on the related issue of non-agency RMBS as a prepayment of such mortgage loan. Any increase in breaches of representations and the consequent repurchases of mortgage loans that result from inadequate underwriting procedures and policies and protections against fraud will have the same effect on the yield on the related non-agency RMBS as an increase in prepayment rates. CMBS are also subject to prepayment risk, as described above. Risk of prepayment may be reduced for commercial real estate property loans containing significant prepayment penalties or prohibitions on principal payments for a period of time following origination. The Fund may also invest in MBS which are IO securities and PO securities. An IO security receives some or all of the interest portion of the underlying collateral and little or no principal. A reference principal value called a notional value is used to calculate the amount Summary of information regarding the Fund (unaudited) (cont’d) of interest due. IO securities are sold at a deep discount to their notional principal amount. A PO security does not receive any interest, is priced at a deep discount to its redemption value and ultimately receives the redemption value. Generally speaking, when interest rates are falling and prepayment rates are increasing, the value of a PO security will rise and the value of an IO security will fall. Conversely, when interest rates are rising and prepayment rates are decreasing, generally the value of a PO security will fall and the value of an IO security will rise. Legal Risks Associated with Non-Agency RMBS. Notwithstanding these protections, an issuer of non-agency RMBS may be exposed to an unquantifiable amount of potential assignee liability because, first, the amount of potential assignee liability under certain predatory lending laws is unclear and has yet to be litigated, and, second, in the event a predatory lending law does not prohibit class action lawsuits, it is possible that an issuer of non-agency RMBS could be liable in damages for more than the original principal amount of the offending loans held by it. In such circumstances the issuer of non-agency RMBS may be forced to seek contribution from other parties, who may no longer exist or have adequate funds available to fund such contribution. In addition, structural and legal risks of non-agency RMBS include the possibility that, in a bankruptcy or similar proceeding involving the originator or the servicer (often the same entity or affiliates), the assets of the issuer could be treated as never having been truly sold by the originator to the issuer and could be substantively consolidated with those of the originator, or the transfer of such assets to the issuer could be voided as a fraudulent transfer. Challenges based on such doctrines could result also in cash flow delays and losses on the related issue of non-agency RMBS. In some cases, servicers of non-agency RMBS have been the subject of legal proceedings involving the origination and/or servicing practices of such servicers. Large groups of private litigants and states attorneys general have brought such proceedings. Because of the large volume of mortgage loans originated and serviced by such servicers, such litigation can cause heightened financial strain on servicers. In other cases, origination and servicing practices may cause or contribute to such strain, because of representation and warranty repurchase liability arising in MBS and mortgage loan sale transactions. Any such financial strain could cause servicers to service below required standards, causing delinquencies and losses in any related MBS transaction to rise, and in extreme cases could cause the servicer to seek the protection of any applicable bankruptcy or insolvency law. In any such proceeding, it is unclear whether the fees that the servicer charges in such transactions would be sufficient to permit that servicer or a successor servicer to service the mortgage loans in such transaction adequately. If such fees had to be increased, it is likely that the most subordinated security holders in such transactions would be effectively required to pay such increased fees. Finally, these entities may be the subject of future laws designed to protect consumers from defaulting on their mortgage loans. Such laws may have an adverse effect on the cash flows paid under such non-agency RMBS. In the past year, a number of lenders specializing in residential mortgages have sought bankruptcy protection, shut down or been refused further financings from their lenders. In addition, certain lenders who service and/or issue non-agency RMBS have announced that they are being investigated by or have received information requests from U.S. federal and/or state authorities, including the Securities and Exchange Commission. As a result of such investigations and other similar investigations and general concerns about the adequacy or accuracy of disclosure of risks to borrowers and their understanding of such risks, U.S. financial regulators have indicated that they may propose new guidelines for the mortgage industry. Guidelines, if introduced, together with the other factors described herein, may make it more difficult for borrowers with weaker credit to refinance, which may lead to further increases in delinquencies, extensions in duration and losses in mortgage-related assets. Furthermore, because some mortgage loans have high recoveries, and as Summary of information regarding the Fund (unaudited) (cont’d) property values decline, increasing loan-to-value ratios, recoveries on some defaulted mortgage loans are more likely to be less than the amounts owed under such mortgage loans, resulting in higher net losses than would have been the case had property values remained the same or increased. | ||||||||||||||||||||||||||||||||||||||||||||||||||
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| Risk [Text Block] | CMBS Risk. The exercise of remedies and successful realization of liquidation proceeds relating to CMBS is also highly dependent on the performance of the servicer or special servicer. In many cases, overall control over the special servicing of related underlying mortgage loans will be held by a “directing certificateholder” or a “controlling class representative,” which is appointed by the holders of the most subordinate class of CMBS in such series. The Fund may not have the right to appoint the directing certificateholder. In connection with the servicing of the specially serviced mortgage loans, the related special servicer may, at the direction of the directing certificateholder, take actions with respect to the specially serviced mortgage loans that could adversely affect the Fund’s interests. There may be a limited number of special servicers available, particularly those that do not have conflicts of interest. Western Asset will value the Fund’s potential CMBS investments based on loss-adjusted yields, taking into account estimated future losses on the mortgage loans included in the securitization’s pool of loans, and the estimated impact of these losses on expected future cash flows. Western Asset’s loss estimates may not prove accurate, as actual results may vary from estimates. In the event that Western Asset overestimates the pool level losses relative to the price the Fund pays for a particular CMBS investment, the Fund may experience losses with respect to such investment. Interest Rate Risk Associated with Non-Agency RMBS and CMBS. The value of fixed rate debt securities can be expected to vary inversely with changes in prevailing interest rates. Fixed rate debt securities with longer maturities, which tend to produce higher yields, are subject to potentially greater capital appreciation and depreciation than securities with shorter maturities. Structural Risks Associated with Non-Agency RMBS and CMBS Summary of information regarding the Fund (unaudited) (cont’d) Subordination Risk Associated with Non-Agency RMBS and CMBS. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Credit Risk and Counterparty Risk [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Credit Risk and Counterparty Risk. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Interests Rate Risk [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Interest Rate Risk | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Leverage Risk [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Leverage Risk. its obligations created by the use of leverage or derivatives. The use of leverage is considered to be a speculative investment practice and may result in the loss of a substantial amount, and possibly all, of the fund’s assets. In addition, the fund’s portfolio will be leveraged if it exercises its right to delay payment on a redemption, and losses will result if the value of the fund’s assets declines between the time a redemption request is deemed to be received by the fund and the time the fund liquidates assets to meet redemption requests. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| ABS Risk [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | ABS Risk. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Below Investment Grade High Yield or Junk Securities Risk [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Below Investment Grade (“High Yield” or “Junk”) Securities Risk. Summary of information regarding the Fund (unaudited) (cont’d) susceptible to adverse events, credit downgrades and negative sentiments and may be difficult to sell at a desired price, or at all, during periods of uncertainty or market turmoil. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Distressed Investments [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Distressed Investments. The Fund intends to invest in distressed investments including non-performing and sub-performing RMBS and CMBS, many of which are not publicly traded and which may involve a substantial degree of risk. In certain periods, there may be little or no liquidity in the markets for these securities or instruments. In addition, the prices of such securities or instruments may be subject to periods of abrupt and erratic market movements and above-average price volatility. It may be more difficult to value such securities and the spread between the bid and asked prices of such securities may be greater than normally expected. If the Western Asset’s evaluation of the risks and anticipated outcome of an investment in a distressed security should prove incorrect, the Fund may lose a substantial portion or all of its investment. Furthermore, investments in assets operating in workout modes or under Chapter 11 of the United States Bankruptcy Code, as amended, and other comparable bankruptcy laws may, in certain circumstances, be subject to certain additional potential liabilities that may exceed the value of the Fund’s original investment. For example, under certain circumstances, lenders who have inappropriately exercised control of the management and policies of a debtor may have their claims subordinated or disallowed or counterclaims may be filed and lenders may be found liable for damages suffered by various parties as a result of such actions. In addition, under certain circumstances, payments to the Fund and distributions by the Fund to its investors may be reclaimed if any such payment or distribution is later determined to have been a fraudulent conveyance or a preferential payment. The Fund is not limited in its ability to invest in distressed investments. Credit Risk Associated with Originators and Servicers of Residential and Commercial Mortgage Loans. borrowers, decreased originations by such originators of mortgage loans and increased delinquencies and defaults on such mortgage loans, as well as from increases in claims for repurchases of mortgage loans previously sold by them under agreements that require repurchase in the event of breaches of representations regarding loan quality and characteristics. Such difficulties may affect the performance of non-agency RMBS and CMBS backed by mortgage loans. Furthermore, the inability of the originator to repurchase such mortgage loans in the event of loan representation breaches or the servicer to repurchase such mortgage loans upon a breach of its servicing obligations also may affect the performance of related non-agency RMBS and CMBS. Delinquencies and losses on, and, in some cases, claims for repurchase by the originator of, mortgage loans originated by some mortgage lenders have increased as a result of inadequate underwriting procedures and policies, including inadequate due diligence, failure to comply with predatory and other lending laws and, particularly in the case of any “no documentation” or “limited documentation” mortgage loans that may support non-agency RMBS, inadequate verification of income and employment history. Delinquencies and losses on, and claims for repurchase of, mortgage loans originated by some mortgage lenders have also resulted from fraudulent activities of borrowers, lenders, appraisers, and other residential mortgage industry participants such as mortgage brokers, including misstatements of income and employment history, identity theft and overstatements of the appraised value of mortgaged properties. Many of these originators and servicers are very highly leveraged. These difficulties may also increase the chances that these entities may default on their warehousing or other credit lines or become insolvent or bankrupt and thereby increase the likelihood that repurchase obligations will not be fulfilled and the potential for loss to holders of non-agency RMBS, CMBS and subordinated security holders. The servicers of non-agency RMBS and CMBS are often the same entities as, or affiliates of, the originators of these mortgage loans. Accordingly, the financial risks relating to originators of non-agency RMBS and CMBS described immediately above also may affect the servicing of non-agency RMBS and CMBS. In the case of such servicers, and other servicers, financial difficulties may have a negative effect on the ability of servicers to pursue collection on mortgage loans that are experiencing increased delinquencies and defaults and to maximize recoveries on sale of underlying properties following foreclosure. Non-agency RMBS and CMBS typically provide that the servicer is required to make advances in respect of delinquent mortgage loans. However, servicers experiencing financial difficulties may not be able to perform these obligations or obligations that they may have to other parties of transactions involving these securities. Like originators, these entities are typically very highly leveraged. Such difficulties may cause servicers to default under their financing arrangements. In certain cases, such entities may be forced to seek bankruptcy protection. Due to the application of the provisions of bankruptcy law, servicers who have sought bankruptcy protection may not be required to advance such amounts. Even Summary of information regarding the Fund (unaudited) (cont’d) if a servicer were able to advance amounts in respect of delinquent mortgage loans, its obligation to make such advances may be limited to the extent that it does not expect to recover such advances due to the deteriorating credit of the delinquent mortgage loans or declining value of the related mortgaged properties. Moreover, servicers may overadvance against a particular mortgage loan or charge too many costs of resolution or foreclosure of a mortgage loan to a securitization, which could increase the potential losses to holders of non-agency RMBS and CMBS. In such transactions, a servicer’s obligation to make such advances may also be limited to the amount of its servicing fee. In addition, if an issue of non-agency RMBS and CMBS provides for interest on advances made by the servicer, in the event that foreclosure proceeds or payments by borrowers are not sufficient to cover such interest, such interest will be paid to the servicer from available collections or other mortgage income, thereby reducing distributions made on the non-agency RMBS and CMBS and, in the case of senior-subordinated non-agency RMBS and CMBS described below, first from distributions that would otherwise be made on the most subordinated non-agency RMBS and CMBS of such issue. Any such financial difficulties may increase the possibility of a servicer termination and the need for a transfer of servicing and any such liabilities or inability to assess such liabilities may increase the difficulties and costs in affecting such transfer and the potential loss, through the allocation of such increased cost of such transfer, to subordinated security holders. There can be no assurance that originators and servicers of mortgage loans will not continue to experience serious financial difficulties or experience such difficulties in the future, including becoming subject to bankruptcy or insolvency proceedings, or that underwriting procedures and policies and protections against fraud will be sufficient in the future to prevent such financial difficulties or significant levels of default or delinquency on mortgage loans. Because the recent financial difficulties experienced by such originators and services is unprecedented and unpredictable, the past performance of the residential and commercial mortgage loans originated and serviced by them (and the corresponding performance of the related non-agency RMBS and CMBS) is not a reliable indicator of the future performance of such residential mortgage loans (or the related non-agency RMBS and CMBS). | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Subprime Mortgage Market Risk [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Subprime Mortgage Market Risk. rates. Also, a number of residential mortgage loan originators have experienced serious financial difficulties or bankruptcy. Largely due to the foregoing, reduced investor demand for mortgage loans and mortgage-related securities and increased investor yield requirements have caused limited liquidity in the secondary market for mortgage-related securities, which can adversely affect the market value of mortgage-related securities. It is possible that such limited liquidity in such secondary markets could continue or worsen. The Fund may acquire non-agency RMBS backed by collateral pools of mortgage loans that have been originated using underwriting standards that are less restrictive than those used in underwriting “prime mortgage loans” and “Alt-A mortgage loans.” These lower standards include mortgage loans made to borrowers having imperfect or impaired credit histories, mortgage loans where the amount of the loan at origination is 80% or more of the value of the mortgage property, mortgage loans made to borrowers with low credit scores, mortgage loans made to borrowers who have other debt that represents a large portion of their income and mortgage loans made to borrowers whose income is not required to be disclosed or verified. Due to economic conditions, including increased interest rates and lower home prices, as well as aggressive lending practices, subprime mortgage loans have in recent periods experienced increased rates of delinquency, foreclosure, bankruptcy and loss, and they are likely to continue to experience delinquency, foreclosure, bankruptcy and loss rates that are higher, and that may be substantially higher, than those experienced by mortgage loans underwritten in a more traditional manner. Thus, because of the higher delinquency rates and losses associated with subprime mortgage loans, the performance of non-agency RMBS backed by subprime mortgage loans that the Fund may acquire could be correspondingly adversely affected, which could adversely impact the Fund’s results of operations, financial condition and business. If the economy of the United States further deteriorates, the incidence of mortgage foreclosures, especially subprime mortgages, may continue to increase, which may adversely affect the value of any MBS owned by the Fund. The U.S. Congress and various government regulatory authorities have discussed the possibility of restructuring mortgages and imposing forbearance requirements on defaulted mortgages. Neither LMPFA nor Western Asset can predict the form any such modifications, forbearance or related regulations might take, and these regulations may adversely affect the value of MBS owned by the Fund. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Risks Related to Investments in Mortgage Whole Loans [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Risks Relating to Investments in Mortgage Whole Loans. Credit Risk Associated With Investments in Mortgage Whole Loans. Summary of information regarding the Fund (unaudited) (cont’d) federal agency or any federally chartered corporation. As a result, a mortgage whole loan is directly exposed to losses resulting from default and foreclosure. Therefore, the value of the underlying property, the creditworthiness and financial position of the borrower, and the priority and enforceability of the lien are each of great importance. Whether or not Legg Mason, Western Asset or their affiliates have participated in the negotiation of the terms of any such mortgages, there can be no assurance as to the adequacy of the protection of the terms of the loan, including the validity or enforceability of the loan and the maintenance of the anticipated priority and perfection of the applicable security interests. Furthermore, claims may be asserted that might interfere with enforcement of the rights of the Fund. In the event of a foreclosure, the Fund may assume direct ownership of the underlying real estate. The liquidation proceeds upon sale of such real estate may not be sufficient to recover the Fund’s cost basis in the loan, resulting in a loss to the Fund. Any costs or delays involved in the effectuation of a foreclosure of the loan or a liquidation of the underlying property will further reduce the proceeds and thus increase the loss. Higher-than-expected rates of default and/or higher-than-expected loss severities on these investments could adversely affect the value of these assets. Accordingly, defaults in the payment of principal and/or interest on the Fund’s residential and commercial whole loans would likely result in the Fund incurring losses of income from, and/or losses in market value relating to, these assets, which could materially adversely affect the Fund’s results of operations. Holders of residential and commercial whole loans are subject to the risk that the related borrowers may default or have defaulted on their obligations to make full and timely payments of principal and interest. A number of factors impact a borrower’s ability to repay including, among other things, changes in employment status, changes in interest rates or the availability of credit, and changes in real estate values. In addition to the credit risk associated with these assets, residential and commercial whole loans are less liquid than certain of the Fund’s other credit sensitive assets, which may make them more difficult to dispose of if the need or desire arises. If actual results are different from the Fund’s assumptions in determining the prices paid to acquire such loans, particularly if the market value of the underlying properties decreases significantly subsequent to purchase, we may incur significant losses, which could materially adversely affect the Fund’s results. Servicing-Related Risks of Mortgage Whole Loans. service these mortgages and/or to competently manage and dispose of REO properties could negatively impact the value of these investments and the Fund’s financial performance. In addition, while we have contracted with third-party servicers to carry out the actual servicing of the loans (including all direct interface with the borrowers), for loans that we purchase together with the related servicing rights, we are nevertheless ultimately responsible, vis-à-vis the borrowers and state and federal regulators, for ensuring that the loans are serviced in accordance with the terms of the related notes and mortgages and applicable law and regulation. In light of the current regulatory environment, such exposure could be significant even though we might have contractual claims against the Fund’s servicers for any failure to service the loans to the required standard. The foreclosure process, especially in judicial foreclosure states such as New York, Florida and New Jersey, can be lengthy and expensive, and the delays and costs involved in completing a foreclosure, and then subsequently liquidating the REO property through sale, may materially increase any related loss. In addition, at such time as title is taken to a foreclosed property, it may require more extensive rehabilitation than we estimated at acquisition. Thus, a material amount of foreclosed residential mortgage loans, particularly in the states mentioned above, could result in significant losses in the Fund’s residential and commercial whole loan portfolio and could materially adversely affect the Fund’s results of operations. Prepayment Risk Associated With Investments in Mortgage Whole Loans We may purchase residential and commercial whole loans that have a higher interest rate than the then prevailing market interest rate. In exchange for this higher interest rate, we may pay a premium to par value to acquire the asset. In accordance with accounting rules, we amortize this premium over the expected term of the asset based on the Fund’s prepayment assumptions. If the asset is prepaid in whole or in part at a faster than expected rate, however, we must expense all or a part of the remaining unamortized portion of the premium that was paid at the time of the purchase, which will adversely affect the Fund’s profitability. Prepayment rates generally increase when interest rates fall and decrease when interest rates rise, but changes in prepayment rates are difficult to predict. House price Summary of information regarding the Fund (unaudited) (cont’d) appreciation, while increasing the value of the collateral underlying the Fund’s residential and commercial whole loans, may increase prepayment rates as borrowers may be able to refinance at more favorable terms. Prepayments can also occur when borrowers default on their residential and commercial mortgages and the mortgages are prepaid from the proceeds of a foreclosure sale of the property (an involuntary prepayment), or when borrowers sell the property and use the sale proceeds to prepay the mortgage as part of a physical relocation. Prepayment rates also may be affected by conditions in the housing and financial markets, increasing defaults on Residential and Commercial mortgage loans, which could lead to an acceleration of the payment of the related principal, general economic conditions and the relative interest rates on fixed-rate mortgages and ARMs. While we seek to manage prepayment risk, in selecting residential and commercial whole loans investments we must balance prepayment risk against other risks, the potential returns of each investment and the cost of hedging the Fund’s risks. No strategy can completely insulate us from prepayment or other such risks, and we may deliberately retain exposure to prepayment or other risks. In addition, a decrease in prepayment rates may adversely affect the Fund’s profitability. When borrowers prepay their residential and commercial mortgage loans at slower than expected rates, prepayments on the residential and commercial whole loans may be slower than expected. These slower than expected payments may adversely affect the Fund’s profitability. We may purchase residential and commercial whole loans that have a lower interest rate than the then prevailing market interest rate. In exchange for this lower interest rate, we may pay a discount to par value to acquire the asset. In accordance with accounting rules, we accrete this discount over the expected term of the asset based on the Fund’s prepayment assumptions. If the asset is prepaid at a slower than expected rate, however, we must accrete the remaining portion of the discount at a slower than expected rate. This will extend the expected life of the asset and result in a lower than expected yield on assets purchased at a discount to par. Geographic Concentration Risk Associated With Residential and Commercial Whole Loans. and acts of terrorism should such developments occur in or near the markets in California in which such properties are located. Other Risks Associated with Mortgage Whole Loans. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Tax Risks [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Tax Risks. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk of Taxable Income in Excess of Economic Income [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Risk of Taxable Income in Excess of Economic Income. Similarly, many of the debt instruments (including MBS) that the Fund purchases will likely have been issued with original issue discount (“OID”), which discount might reflect doubt as to whether the entire principal amount of such debt instruments will ultimately prove to be collectible. The Fund will be required to report such OID based on a constant yield method and income will be accrued and be currently taxable based on the assumption that all future projected payments due on such debt instruments will be made. Summary of information regarding the Fund (unaudited) (cont’d) Finally, in the event that any debt instruments (including MBS) acquired by the Fund are delinquent as to mandatory principal and interest payments, or in the event payments with respect to a particular debt instrument are not made when due, the Fund may nonetheless be required to continue to recognize the unpaid interest as taxable income as it accrues, despite doubt as to its ultimate collectability. Similarly, the Fund may be required to accrue interest income with respect to subordinate MBS at the stated rate regardless of whether corresponding cash payments are received or are ultimately collectible. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Risks Associated with the Funds Ability to Satisfy Regulated Investment Company Distribution Requirements [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Risks Associated with the Fund’s Ability To Satisfy Regulated Investment Company Distribution Requirements. The Fund may find it difficult or impossible to meet distribution requirements in certain circumstances. Due to the nature of the assets in which the Fund intends to invest, the Fund’s taxable income may exceed the Fund’s net income as determined based on generally accepted accounting principles (“GAAP”) because, for example, realized capital losses will be deducted in determining the Fund’s GAAP net income but may not be deductible in computing the Fund’s taxable income required to be distributed. In addition, the Fund may invest in assets, including debt instruments requiring the Fund to accrue OID, that generate taxable income (referred to as “phantom income”) in excess of economic income or in advance of the corresponding cash flow from the assets. In addition, if the debt instruments provide for “payment-in-kind” or PIK interest, the Fund may recognize OID for federal income tax purposes. Moreover, the Fund may acquire distressed debt investments that are subsequently modified by agreement with the borrower. If the amendments to the outstanding debt are “significant modifications” under the applicable Treasury regulations, the modified debt may be considered to have been reissued to the Fund in a debt-for-debt exchange with the borrower. In that event, if the debt is considered to be “publicly traded” for federal income tax purposes, the modified debt in the hands of the Fund may be considered to have been issued with OID to the extent the fair-market value of the modified debt is less than the principal amount of the outstanding debt. Also, certain previously modified debt that the Fund acquires in the secondary market may be considered to have been issued with OID at the time it was modified. In general, the Fund will be required to accrue OID on a debt instrument as taxable income in accordance with applicable federal income tax rules even though no cash payments may be received on such debt instrument. In the event a borrower with respect to a particular debt instrument encounters financial difficulty rendering it unable to pay stated interest as due, the Fund may nonetheless be required to continue to recognize the unpaid interest as taxable income. Similarly, the Fund may be required to accrue interest income with respect to subordinate MBS at the stated rate regardless of when their corresponding cash payments are received. Further, the Fund may invest in assets that accrue market discount income, which may result in the recognition of taxable income in excess of the Fund’s economic gain in certain situations or the deferral of a portion of the Fund’s interest deduction paid on debt incurred to acquire or carry such assets. Due to each of these potential timing differences between income recognition or expense deduction and cash receipts or disbursements, there is a significant risk that the Fund may have substantial taxable income in excess of cash available for distribution. To satisfy its distribution requirements, the Fund may borrow on unfavorable terms or distribute amounts that would otherwise be invested in future acquisitions, capital expenditures or repayment of debt. In addition, the Fund may make distributions in its Common Stock to satisfy the distribution requirements necessary to maintain the Fund’s status as a regulated investment company for U.S. federal income tax purposes and to avoid U.S. federal income and excise taxes, but no assurances can be given in this regard. Moreover, if the Fund’s only feasible alternative were to make a taxable distribution of the Fund’s Common Stock to comply with the regulated investment company distribution requirements for any taxable year and the value of the Fund’s Common Stock was not sufficient at such time to make a distribution to its Common Stockholders in an amount at least equal to the minimum amount required to comply with such regulated investment company distribution requirements, the Fund would generally fail to qualify as a regulated investment company for such taxable year. Despite undertaking the efforts mentioned in the previous paragraph, the Fund may not be able to distribute the amounts necessary to satisfy the distribution requirements necessary to maintain its regulated investment company status for U.S. federal income taxes and to Summary of information regarding the Fund (unaudited) (cont’d) avoid U.S. federal income and excise taxes. If the Fund were unable to satisfy the 90% distribution requirement or otherwise were to fail to qualify as a regulated investment company in any year, material adverse tax consequences would result to investors. The Fund would be taxed in the same manner as an ordinary corporation and distributions to the Fund’s Common Stockholders would not be deductible by the Fund in computing its taxable income. To qualify again to be taxed as a regulated investment company in a subsequent year, the Fund would be required to distribute to its Common Stockholders its earnings and profits attributable to non-regulated investment company years reduced by an interest charge on 50% of such earnings and profits payable by the Fund to the Internal Revenue Service (“IRS”). In addition, if the Fund failed to qualify as a regulated investment company for a period greater than two taxable years, then the Fund would be required to elect to recognize and pay tax on any net built-in gain (the excess of aggregate gain, including items of income, over aggregate loss that would have been realized if the Fund had been liquidated) or, alternatively, be subject to taxation on such built-in gain recognized for a period of 5 years, in order to qualify as a regulated investment company in a subsequent year. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Government Intervention in Financial Markets Risk [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Government Intervention in Financial Markets Risk. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Currency Risk [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Currency Risk. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Extension Risk [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Extension Risk. the Fund to lengthen due to a drop in mortgage prepayments. This will increase both the sensitivity to rising interest rates and the potential for price declines of the Fund. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Widening Risk [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | “ Widening” Risk. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Management Risk [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Management Risk. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Credit Crisis Liquidity and Volatility Risk [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Credit Crisis Liquidity and Volatility Risk. The debt and equity capital markets in the United States have been negatively impacted by significant write-offs in the financial services sector relating to subprime mortgages and the re-pricing of credit risk in the broadly syndicated market, among other things. These events, along with the deterioration of the housing market and the failure of major financial institutions, have led to worsening general economic conditions, which have materially and adversely impacted the broader financial and credit markets and have reduced the availability of debt and equity capital for the market as a whole and financial firms in particular. These developments may increase the volatility of the value of securities owned by the Fund and also may make it more difficult for the Fund to accurately value securities or to sell securities on a timely basis. These developments have adversely affected the broader economy, and may continue to do so, which in turn may adversely affect the ability of issuers of securities owned by the Fund to make payments of principal and interest when due, lead to lower credit ratings and increase defaults. Such developments could, in turn, reduce the value of securities owned by the Fund and adversely affect the net asset value of the Fund. In addition, the prolonged continuation or further deterioration of current market conditions could adversely impact the Fund’s portfolio. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Investment Focus [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Investment Focus. The Fund employs a variety of proprietary risk analytics and risk management tools in connection with making and monitoring portfolio investments. Prospective investors should be aware that no risk management or portfolio analytics system is fail-safe, and no assurance can be given that risk frameworks employed by either LMPFA and/or Western Asset (e.g., stop-win, stop-loss, Sharpe Ratios, loss limits, value-at-risk or any other methodology now known or later developed) will achieve their objectives and prevent or otherwise limit substantial losses. No assurance can be given that the risk management systems and techniques or pricing models will accurately predict future trading patterns or the manner in which investments are priced in financial markets in the future. In addition, certain risk management tools may rely on certain assumptions (e.g., historical interest rates, anticipated rate trends) and such assumptions may prove incorrect. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Competition for Investment Opportunities [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Competition for Investment Opportunities. will be able to identify and make investments that are consistent with its investment objectives. Additional third-party managed investment funds with similar objectives may be formed in the future. Given the foregoing, it is possible that competition for appropriate portfolio investments may increase, thus reducing the number of attractive portfolio investment opportunities available to the Fund and may adversely affect the terms upon which investments can be made. There can be no assurance that the Fund will be able to locate, consummate and exit investments that satisfy its investment objective, or that it will be able to invest the net proceeds from this offering in MBS to the extent necessary to achieve its investment objectives. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Inflation Deflation Risk [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Inflation/Deflation Risk. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Reinvestment Risk [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
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| Risk [Text Block] | Reinvestment Risk | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Reverse Repurchase Agreements Risk [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Reverse Repurchase Agreements Risk. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Repurchase Agreements Risk [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Repurchase Agreements Risk. Summary of information regarding the Fund (unaudited) (cont’d) institution such as a bank, savings and loan association or broker-dealer. The agreement provides that the Fund will sell the securities back to the institution at a fixed time in the future. The Fund does not bear the risk of a decline in the value of the underlying security unless the seller defaults under its repurchase obligation. In the event of the bankruptcy or other default of a seller of a repurchase agreement, the Fund could experience both delays in liquidating the underlying securities and losses, including (1) possible decline in the value of the underlying security during the period in which the Fund seeks to enforce its rights thereto; (2) possible lack of access to income on the underlying security during this period; and (3) expenses of enforcing its rights. While repurchase agreements involve certain risks not associated with direct investments in debt securities, the Fund follows procedures approved by the Fund’s Board of Directors that are designed to minimize such risks. These procedures include effecting repurchase transactions only with large, well-capitalized and well-established financial institutions whose financial condition will be continually monitored by Western Asset. In addition, as described above, the value of the collateral underlying the repurchase agreement will be at least equal to the repurchase price, including any accrued interest earned on the repurchase agreement. In the event of a default or bankruptcy by a selling financial institution, the Fund generally will seek to liquidate such collateral. However, the exercise of the Fund’s right to liquidate such collateral could involve certain costs or delays and, to the extent that proceeds from any sale upon a default of the obligation to repurchase were less than the repurchase price, the Fund could suffer a loss. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Variable Debt Risk [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Variable Debt Risk. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Structured Notes and Related Instruments Risk [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Structured Notes and Related Instruments Risk. depending on a variety of factors, including the volatility of the embedded index and the effect of changes in the embedded index on principal and/or interest payments. The rate of return on structured notes may be determined by applying a multiplier to the performance or differential performance of the referenced index(es) or other asset(s). Application of a multiplier involves leverage that will serve to magnify the potential for gain and the risk of loss. Insolvency Considerations with Respect to Issuers of Indebtedness. Portfolio Valuation for Financial Accounting and Other Reporting Purposes. Summary of information regarding the Fund (unaudited) (cont’d) Fund from time to time, the liquidation values of portfolio investments may differ significantly from the valuations of such portfolio investments derived from the valuation methods described herein. Some of the Fund’s portfolio investments will be in the form of securities that are not publicly traded. The fair value of securities and other investments that are not publicly traded may not be readily determinable. The Fund will value these investments quarterly at fair value, as determined in accordance with Statement of Financial Accounting Standards, or SFAS, No. 157, “Fair Value Measurements,” which may include unobservable inputs. Because such valuations are subjective, the fair value of certain of the Fund’s assets may fluctuate over short periods of time and the Fund’s determinations of fair value may differ materially from the values that would have been used if a ready market for these securities existed. The value of the Fund’s Common Stock could be adversely affected if the Fund’s determinations regarding the fair value of these investments were materially higher than the values that it ultimately realizes upon their disposal. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Inverse Floating Rate Securities and Tender Option Bonds Risk [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Inverse Floating Rate Securities and Tender Option Bonds Risk. Inverse floating rate securities have interest rate adjustment formulas which generally reduce or, in the extreme, eliminate the interest paid to the Fund when short-term interest rates rise, and increase the interest paid to the Fund when short-term interest rates fall. Inverse floating rate securities have varying degrees of liquidity, and the market for these securities is relatively volatile. These securities tend to underperform the market for fixed-rate bonds in a rising interest rate environment, but tend to outperform the market for fixed-rate bonds when interest rates decline. Shifts in long-term interest rates may, however, alter this tendency. During times of reduced market liquidity, such as at the present, the Fund may not be able to sell MBS readily at prices reflecting the values at which the securities are carried on the Fund’s books. Sales of large blocks of MBS by market participants, such as the Fund, that are seeking liquidity can further reduce MBS prices in an illiquid market. The Fund may seek to make sales of large blocks of MBS as part of its investment strategy or it may be required to raise cash to re-collateralize, unwind or “collapse” tender option bond trusts that issued inverse floating rate securities to the Fund or to make payments to such trusts to enable them to pay for tenders of the short-term securities they have issued if the remarketing agents for those MBS are unable to sell the short-term securities in the marketplace to other buyers. The Fund’s potential exposure to losses related to or on inverse floating rate securities may increase beyond the value of the Fund’s inverse floater investments as the Fund may potentially be liable to fulfill all amounts owed to holders of the floating rate certificates. Although volatile, inverse floating rate securities typically offer the potential for yields exceeding the yields available on fixed-rate bonds with comparable credit quality, coupon, call provisions and maturity. These securities usually permit the investor to convert the floating rate to a fixed rate (normally adjusted downward), and this optional conversion feature may provide a partial hedge against rising rates if exercised at an opportune time. Investment in inverse floating rate securities may amplify the effects of the Fund’s use of leverage. Any economic effect of leverage through the Fund’s purchase of inverse floating rate securities will create an opportunity for increased Common Stock net income and returns, but may also result in losses if the cost of leverage exceeds the value of the securities underlying the tender option bond trust or the return on the inverse floating rate securities purchased by the Fund. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Other Investment Companies Risk [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Other Investment Companies Risk. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Risks Related to Fund Distributions [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Risks Related to Fund Distributions. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Derivatives Risk [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Derivatives Risk. Summary of information regarding the Fund (unaudited) (cont’d) reduce opportunities for gains when market prices, interest rates, currencies, or the derivatives themselves behave in a way not anticipated by the Fund. Using derivatives also can have a leveraging effect and increase Fund volatility. Certain derivatives have the potential for unlimited loss, regardless of the size of the initial investment. Derivatives may not be available at the time or price desired, may be difficult to sell, unwind or value, and the counterparty may default on its obligations to the Fund. Derivatives are generally subject to the risks applicable to the assets, rates, indices or other indicators underlying the derivative. The value of a derivative may fluctuate more than the underlying assets, rates, indices or other indicators to which it relates. Use of derivatives may have different tax consequences for the Fund than an investment in the underlying security, and those differences may affect the amount, timing and character of income distributed to shareholders. The U.S. government and foreign governments are in the process of adopting and implementing regulations governing derivatives markets, including mandatory clearing of certain derivatives, margin and reporting requirements. The ultimate impact of the regulations remains unclear. Additional regulation of derivatives may make derivatives more costly, limit their availability or utility, otherwise adversely affect their performance or disrupt markets. Effective August 19, 2022, the Fund began operating under Rule 18f-4 under the 1940 Act which, among other things, governs the use of derivative investments and certain financing transactions (e.g. reverse repurchase agreements) by registered investment companies. Among other things, Rule 18f-4 requires funds that invest in derivative instruments beyond a specified limited amount to apply a value at risk (VaR) based limit to their use of certain derivative instruments and financing transactions and to adopt and implement a derivatives risk management program. A fund that uses derivative instruments in a limited amount is not subject to the full requirements of Rule 18f-4. Compliance with Rule 18f-4 by the Fund could, among other things, make derivatives more costly, limit their availability or utility, or otherwise adversely affect their performance. Rule 18f-4 may limit the Fund’s ability to use derivatives as part of its investment strategy. Credit default swap contracts involve heightened risks and may result in losses to the Fund. Credit default swaps may be illiquid and difficult to value. When the Fund sells credit protection via a credit default swap, credit risk increases since the Fund has exposure to both the issuer whose credit is the subject of the swap and the counterparty to the swap. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Short Sales Risk [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Short Sales Risk. right to acquire the security sold short at no additional cost. The Fund’s loss on a short sale theoretically could be unlimited in a case where the Fund is unable, for whatever reason, to close out its short position. In addition, the Fund’s short selling strategies may limit its ability to benefit from increases in the markets. If the Fund engages in short sales, it will segregate liquid assets, enter into offsetting transactions or own positions covering its obligations; however, such segregation and cover requirements will not limit or offset losses on related positions. Short selling also involves a form of financial leverage that may exaggerate any losses realized by the Fund. Also, there is the risk that the counterparty to a short sale may fail to honor its contractual terms, causing a loss to the Fund. The Fund will incur transaction costs with any short sales, which will be borne by shareholders. Finally, regulations imposed by the SEC or other regulatory bodies relating to short selling may restrict the Fund’s ability to engage in short selling. The Fund’s obligation to replace a borrowed security is secured by collateral deposited with the broker-dealer, usually cash, U.S. government securities or other liquid securities similar to those borrowed. The Fund is also required to segregate similar collateral to the extent, if any, necessary so that the value of both collateral amounts in the aggregate is at all times equal to at least 100% of the current market value of the security sold short. Depending on arrangements made with the broker-dealer from which the Fund borrowed the security regarding payment over of any payments received by us on such security, the Fund may not receive any payments (including interest) on the collateral deposited with such broker-dealer. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Risks of Short Economic Exposure Through Derivatives [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Risks of Short Economic Exposure Through Derivatives. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Liquidity Risk [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Liquidity Risk. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| When Issued and Delayed Delivery Transactions Risk [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | When-Issued and Delayed-Delivery Transactions Risk Summary of information regarding the Fund (unaudited) (cont’d) purchased or sold by the Fund with payment and delivery taking place in the future to secure an advantageous yield or price. Securities purchased on a when-issued or delayed-delivery basis may expose the Fund to counterparty risk of default as well as the risk that securities may experience fluctuations in value prior to their actual delivery. The Fund will not accrue income with respect to a when-issued or delayed-delivery security prior to its stated delivery date. Purchasing securities on a when-issued or delayed-delivery basis can involve the additional risk that the price or yield available in the market when the delivery takes place may not be as favorable as that obtained in the transaction itself. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Non Diversification Risk [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Non-Diversification Risk. Risks Related to Potential Conflicts of Interest. transaction, or both, to the detriment or benefit of one or more other funds and accounts. For example, a portfolio manager may determine that it would be in the interest of another account to sell a security that the Fund holds, potentially resulting in a decrease in the market value of the security held by the Fund. The portfolio managers may also engage in cross trades between funds and accounts, may select brokers or dealers to execute securities transactions based in part on brokerage and research services provided to LMPFA or Western Asset which may not benefit all funds and accounts equally and may receive different amounts of financial or other benefits for managing different funds and accounts. Finally, LMPFA or its affiliates may provide more services to some types of funds and accounts than others. There is no guarantee that the policies and procedures adopted by LMPFA, Western Asset and the Fund will be able to identify or mitigate the conflicts of interest that arise between the Fund and any other investment funds or accounts that LMPFA and/or Western Asset may manage or advise from time to time. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Portfolio Turnover Risk [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Portfolio Turnover Risk. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Anti Takeover Provisions Risk [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Anti-Takeover Provisions Risk. ec Summary of information regarding the Fund (unaudited) (cont’d) from seeking to obtain control of the Fund. There can be no assurance, however, that such provisions will be sufficient to deter professional investors that seek to cause the Fund to take actions that may not be aligned with the interests of long-term shareholders in order to allow the professional investor to arbitrage the Fund’s market price. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Market Event Risk [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Market Events Risk. The long-term impact of the COVID-19 pandemic and its subsequent variants on economies, markets, industries and individual issuers is not known. Some sectors of the economy and individual issuers have experienced or may experience particularly large losses. Periods of extreme volatility in the financial markets, reduced liquidity of many instruments, increased government debt, inflation, and disruptions to supply chains, consumer demand and employee availability, may continue for some time. The U.S. government and the Federal Reserve, as well as certain foreign governments and central banks, took extraordinary actions to support local and global economies and the financial markets in response to the COVID-19 pandemic. This and other government intervention into the economy and financial markets may not work as intended, and have resulted in a large expansion of government deficits and debt, the long term consequences of which are not known. In addition, the COVID-19 pandemic, and measures taken to mitigate its effects, could result in disruptions to the services provided to the fund by its service providers. Raising the ceiling on U.S. government debt has become increasingly politicized. Any failure to increase the total amount that the U.S. government is authorized to borrow could lead to a default on U.S. government obligations, with unpredictable consequences for economies and markets in the U.S. and elsewhere. Recently, inflation and interest rates have increased and may rise further. These circumstances could adversely affect the value and liquidity of the fund’s investments, impair the fund’s ability to satisfy redemption requests, and negatively impact the fund’s performance. The United States and other countries are periodically involved in disputes over trade and other matters, which may result in tariffs, investment restrictions and adverse impacts on affected companies and securities. For example, the United States has imposed tariffs and other trade barriers on Chinese exports, has restricted sales of certain categories of goods to China, and has established barriers to investments in China. Trade disputes may adversely affect the economies of the United States and its trading partners, as well as companies directly or indirectly affected and financial markets generally. The United States government has prohibited U.S. persons from investing in Chinese companies designated as related to the Chinese military. These and possible future restrictions could limit the fund’s opportunities for investment and require the sale of securities at a loss or make them illiquid. Moreover, the Chinese government is involved in a longstanding dispute with Taiwan that has included threats of invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt unification of Taiwan by force, or if other geopolitical conflicts develop or get worse, economies, markets and individual securities may be severely affected both regionally and globally, and the value of the fund’s assets may go down. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Legal and Regulatory Risk [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Legal and Regulatory Risk. In addition, the securities and futures markets are subject to comprehensive statutes, regulations and margin requirements. The CFTC, the SEC, the Federal Deposit Insurance Corporation, other regulators and self-regulatory organizations and exchanges are authorized under these statutes, regulations and otherwise to take extraordinary actions in the event of market emergencies. The Fund and the Investment Manager have historically Summary of information regarding the Fund (unaudited) (cont’d) been eligible for exemptions from certain regulations. However, there is no assurance that the Fund and LMPFA will continue to be eligible for such exemptions. The U.S. Government enacted legislation that provides for new regulation of the derivatives market, including clearing, margin, reporting, recordkeeping, and registration requirements. Although the CFTC has released final rules relating to clearing, reporting, recordkeeping and registration requirements under the legislation, certain of the provisions are subject to further final rule making, and thus its ultimate impact remains unclear. New regulations could, among other things, restrict the Fund’s ability to engage in derivatives transactions (for example, by making certain types of derivatives transactions no longer available to the Fund) and/or increase the costs of such derivatives transactions (for example, by increasing margin or capital requirements), and the Fund may be unable to execute its investment strategies as a result. It is unclear how the regulatory changes will affect counterparty risk. The CFTC and certain futures exchanges have established limits, referred to as “position limits,” on the maximum net long or net short positions which any person may hold or control in particular options and futures contracts; those position limits may also apply to certain other derivatives positions the Fund may wish to take. All positions owned or controlled by the same person or entity, even if in different accounts, may be aggregated for purposes of determining whether the applicable position limits have been exceeded. Thus, even if the Fund does not intend to exceed applicable position limits, it is possible that different clients managed by the Investment Manager and its affiliates may be aggregated for this purpose. Therefore it is possible that the trading decisions of the Investment Manager may have to be modified and that positions held by the Fund may have to be liquidated in order to avoid exceeding such limits. The modification of investment decisions or the elimination of open positions, if it occurs, may adversely affect the performance of the Fund. The SEC has in the past adopted interim rules requiring reporting of all short positions above a certain de minimis threshold and may adopt rules requiring monthly public disclosure in the future. In addition, other non-U.S. jurisdictions where the Fund may trade have adopted reporting requirements. To the extent that the Fund takes a short position, if such short position or strategy become generally known, it could have a significant effect on the Fund’s ability to implement its investment strategy. In particular, it would make it more likely that other investors could cause a “short squeeze” in the securities held short by the Fund forcing the Fund to cover its positions at a loss. Such reporting requirements also may limit the Investment Manager’s ability to access management and other personnel at certain companies where the Fund seeks to take a short position. In addition, if other investors engage in copycat behavior by taking positions in the same issuers as the Fund, the cost of borrowing securities to sell short could increase drastically and the availability of such securities to the Fund could decrease drastically. Such events could make the Fund unable to execute its investment strategy. In addition, the SEC and other regulatory and self-regulatory authorities have implemented various rules and may adopt additional rules in the future that may impact those engaging in short selling activity. If additional rules were adopted regarding short sales, they could restrict the Fund’s ability to engage in short sales in certain circumstances, and the Fund may be unable to execute certain investment strategies as a result. The SEC and regulatory authorities in other jurisdictions may adopt (and in certain cases, have adopted) bans on short sales of certain securities in response to market events. Bans on short selling may make it impossible for the Fund to execute certain investment strategies. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| LIBOR Risk [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | LIBOR Risk. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Valuation Risk [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Valuation Risk Summary of information regarding the Fund (unaudited) (cont’d) These differences may increase significantly and affect Fund investments more broadly during periods of market volatility. The Fund’s ability to value its investments may be impacted by technological issues and/or errors by pricing services or other third party service providers. The valuation of the Fund’s investments involves subjective judgment. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Operational Risk [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Operational risk. | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Cybersecurity Risk [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Risk [Text Block] | Cybersecurity risk. . | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Common Shares [Member] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Other Annual Expenses [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Basis of Transaction Fees, Note [Text Block] | Percentage of Net Assets Attributable to Common Shares | ||||||||||||||||||||||||||||||||||||||||||||||||||
| General Description of Registrant [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Lowest Price or Bid | 10.11 | $ 10.32 | $ 10.17 | $ 10.25 | 10.47 | $ 10.95 | $ 11.4 | $ 13.09 | 15.09 | $ 15.33 | $ 14.67 | $ 14.02 | 12.76 | $ 12.54 | $ 10.86 | $ 11.83 | |||||||||||||||||||||||||||||||||||
| Highest Price or Bid | 11.24 | 11.25 | 10.8 | 11.51 | 11.48 | 12.84 | 13.45 | 15.52 | 16.13 | 16.24 | 15.64 | 14.96 | 14.41 | 14.98 | 14.71 | 21.38 | |||||||||||||||||||||||||||||||||||
| Share Price | 11.17 | 10.71 | 10.58 | 10.45 | 10.77 | 11.11 | 11.68 | 13.37 | 15.21 | 15.46 | 15.59 | 14.64 | 14.18 | 13.12 | 14.67 | 12.8 | $ 11.17 | 10.77 | 15.21 | 14.18 | |||||||||||||||||||||||||||||||
| NAV Per Share | [9] | $ 12.05 | $ 11.96 | $ 12.02 | $ 12.16 | $ 12.12 | $ 12.75 | $ 13.24 | $ 14.3 | $ 15.4 | $ 15.43 | $ 15.08 | $ 14.92 | $ 14.96 | $ 14.25 | $ 14.08 | $ 12.47 | $ 12.05 | $ 12.12 | $ 15.4 | $ 14.96 | ||||||||||||||||||||||||||||||
| Latest Premium (Discount) to NAV [Percent] | (7.30%) | [10] | (10.45%) | [10] | (11.98%) | [10] | (14.06%) | [10] | (11.14%) | [10] | (12.86%) | [10] | (11.78%) | [10] | (6.50%) | [10] | (1.23%) | [10] | 0.19% | [10] | 3.38% | [10] | (1.88%) | [10] | (5.21%) | [10] | (7.93%) | [10] | 4.19% | [10] | 2.65% | [10] | 7.30% | ||||||||||||||||||
| Capital Stock, Long-Term Debt, and Other Securities [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Outstanding Security, Held [Shares] | 11,383,541 | ||||||||||||||||||||||||||||||||||||||||||||||||||
| [1]Represents the estimated commission with respect to the Common Stock being sold in at-the-market offerings. JonesTrading will be entitled to compensation of up to 1.00% of the gross proceeds of the sale of any Common Stock under the Sales Agreement, with the exact amount of such compensation to be mutually agreed upon in writing by the Fund and JonesTrading from time to time.[2]Common Stockholders will pay brokerage charges if they direct the Plan Agent to sell Common Stock held in a dividend reinvestment account. There are no fees charged to stockholders for participating in the Fund’s dividend reinvestment plan. However, stockholders participating in the Plan that elect to sell their shares obtained pursuant to the plan would pay $5.00 per transaction to sell shares.[3]Costs incurred by the Fund in connection with the shelf offering are recorded as a prepaid expense. These costs are amortized on a pro-rata basis as shares are sold and are presented as a reduction to the net proceeds from sale of shares. Any deferred charges remaining at the end of the life of the shelf offering period will be expensed.[4]The Investment Manager receives an annual fee, payable monthly, in an amount equal to 1.00% of the Fund’s average daily Managed Assets. “Managed Assets” means net assets plus the amount of any outstanding borrowings used for leverage and assets attributable to any preferred stock that may be outstanding. If the Fund were to use leverage, the amount of management fees paid to the Investment Manager will be higher than if the Fund does not use leverage because the fees paid are calculated on the Funds Managed Assets.[5]The Fund enters into reverse repurchase agreements. The expenses and rates associated with leverage may vary as and when Borrowings or issuances of Preferred Stock are made. “Interest Payments on Borrowed Funds” reflects an annualized interest charge based on the interest rate and borrowings in effect on December 31, 2023.[6]Expenses based on amounts incurred in the fiscal year ended December 31, 2023.[7]The Fund had open reverse repurchase agreements at December 31, 2023, 2022, 2021, 2015, 2014 and 2013.[8]Not applicable, as these senior securities were not registered for public trading.[9]NAV per share is determined as of close of business on the last day of the relevant quarter and therefore may not reflect the NAV per share on the date of the high and low closing sales prices, which may or may not fall on the last day of the quarter.[10]Calculated as of the quarter-end closing sales price divided by the quarter-end NAV. | |||||||||||||||||||||||||||||||||||||||||||||||||||
