| N-2 - USD ($) | | 2 Months Ended | 3 Months Ended | 12 Months Ended |
| Sep. 30, 2020 | Sep. 30, 2020 | Sep. 30, 2020 | Sep. 30, 2024 | Sep. 30, 2023 | Sep. 30, 2022 | Sep. 30, 2021 |
| Cover [Abstract] | | | | | | | |
| Entity Central Index Key | | | | 0001788420 | | | |
| Amendment Flag | | | | false | | | |
| Document Type | | | | N-CSR | | | |
| Entity Registrant Name | | | | KEYSTONE PRIVATE INCOME FUND | | | |
| Financial Highlights [Abstract] | | | | | | | |
| Senior Securities [Table Text Block] | | | | For the For the For the For the For the Period Net Asset Value, beginning of year/period $ 100.38 $ 101.13 $ 101.13 $ 100.00 $ 100.00 Income from Investment Operations: Net investment 1 11.33 9.68 9.96 9.08 — Net realized and unrealized gain (loss) on investments 2 (0.14 ) (0.76 ) 0.13 (0.75 ) — Total from investment operations 11.19 8.92 10.09 8.33 — Distributions to investors: From net investment income (11.39 ) (9.67 ) (10.09 ) (7.20 ) — Total distributions to investors (11.39 ) (9.67 ) (10.09 ) (7.20 ) — Net Asset Value, end of year/period $ 100.18 $ 100.38 $ 101.13 $ 101.13 $ 100.00 Total Return 3 11.76 % 9.22 % 10.44 % 8.57 % 0.00 % 4 Ratios and Supplemental Data: Net Assets, end of year/period (in thousands) $ 34,294 $ 29,926 $ 12,122 $ 2,391 $ 62 Net expenses 4.87 % 5 4.53 % 6 4.82 % 7 4.36 % 8 0.00 % 4,10 Net investment income 11.32 % 5 9.61 % 6 9.85 % 7 8.98 % 8 0.00 % 4,10 Senior Securities Total Amount Outstanding exclusive of Treasury Securities Borrowings-Revolving Loan Agreement (in thousands) 61,964 60,659 64,926 29,433 5,000 Asset Coverage Per $1,000 of Borrowings Borrowings-Revolving Loan Agreement 23,662 18,106 11,710 12,037 14,265 Portfolio Turnover 9 56 % 49 % 63 % 53 % 1 % 4 * 1 Per share data is computed using the average shares method. 2 Realized and unrealized gains and losses per share in this caption are balancing amounts necessary to reconcile the change in net asset value per share for the period, and may not reconcile with the aggregate gains and losses in the Statement of Operations due to share transactions for the period. 3 Total return based on per unit net asset value reflects the change in net asset value based on the effects of the performance of the Fund during the period and assumes distributions, if any, were reinvested. Total returns shown exclude the effect of applicable sales charges. 4 Class D Shares commencement occurred after income and expense were allocated as of September 30, 2020. 5 If distribution and servicing fees of 0.90%, incentive fees of 2.01%, line of credit expenses of 0.25%, and other transaction related expenses of 0.02% had been excluded, the expense ratios would have been decreased by 3.18%, and the income ratios increased by 3.18%, for the year ended September 30, 2024. 6 If distribution and servicing fees of 0.90%, incentive fees of 1.64%, line of credit expenses of 0.20%, and other transaction related expenses of 0.06% had been excluded, the expense ratios would have been decreased by 2.80%, and the income ratios increased by 2.80%, for the year ended September 30, 2023. 7 If distribution and servicing fees of 0.90%, incentive fees of 1.90%, line of credit expenses of 0.16%, and other transaction related expenses of 0.05% had been excluded, the expense ratios would have been decreased by 3.01%, and the income ratios increased by 3.01%, for the year ended September 30, 2022. 8 If distribution and servicing fees of 0.91%, incentive fees of 1.74%, line of credit expenses of 0.13%, and other transaction related expenses of 0.06% had been excluded, the expense ratios would have been decreased by 2.84%, and the income ratios increased by 2.84%, for the year ended September 30, 2021. 9 Calculated at Fund level. 10 For the For the Period Net Asset Value, beginning of year/period $ 100.53 $ 101.28 $ 101.28 $ 100.58 $ 100.00 Income from Investment Operations: Net investment 1 12.00 10.40 10.71 9.12 1.37 Net realized and unrealized gain (loss) on investments 2 (0.14 ) (0.81 ) 0.05 (0.16 ) 0.60 Total from investment operations 11.86 9.59 10.76 8.96 1.97 Distributions to investors: From net investment income (12.06 ) (10.34 ) (10.76 ) (8.26 ) (1.39 ) Total distributions to investors (12.06 ) (10.34 ) (10.76 ) (8.26 ) (1.39 ) Net Asset Value, end of year/period $ 100.33 $ 100.53 $ 101.28 $ 101.28 $ 100.58 Total Return 3 12.48 % 9.93 % 11.16 % 9.21 % 1.97 % 4 Ratios and Supplemental Data: Net Assets, end of year/period (in thousands) $ 174,521 $ 155,996 $ 117,699 $ 70,988 $ 20,726 Net expenses 4.23 % 6 3.90 % 7 4.18 % 8 4.12 % 9 3.43 % 5,10 Net investment income 11.97 % 6 10.31 % 7 10.58 % 8 9.00 % 9 6.12 % 5,10 Senior Securities Total Amount Outstanding exclusive of Treasury Securities Borrowings-Revolving Loan Agreement (in thousands) 61,964 60,659 64,926 29,433 5,000 Asset Coverage Per $1,000 of Borrowings Borrowings-Revolving Loan Agreement 23,662 18,106 11,710 12,037 14,265 Portfolio Turnover 11 56 % 49 % 63 % 53 % 1 % 4 * 1 Per share data is computed using the average shares method. 2 Realized and unrealized gains and losses per share in this caption are balancing amounts necessary to reconcile the change in net asset value per share for the period, and may not reconcile with the aggregate gains and losses in the Statement of Operations due to share transactions for the period. 3 Total return based on per unit net asset value reflects the change in net asset value based on the effects of the performance of the Fund during the period and assumes distributions, if any, were reinvested. Total returns shown exclude the effect of applicable sales charges. 4 Not annualized. 5 Annualized, except for incentive fees. 6 If distribution and servicing fees of 0.25%, incentive fees of 2.02%, line of credit expenses of 0.25%, and other transaction related expenses of 0.02% had been excluded, the expense ratios would have been decreased by 2.54%, and the income ratios increased by 2.54%, for the year ended September 30, 2024. 7 If distribution and servicing fees of 0.25%, incentive fees of 1.65%, line of credit expenses of 0.20%, and other transaction related expenses of 0.06% had been excluded, the expense ratios would have been decreased by 2.16%, and the income ratios increased by 2.16%, for the year ended September 30, 2023. 8 If distribution and servicing fees of 0.25%, incentive fees of 1.92%, line of credit expenses of 0.16%, and other transaction related expenses of 0.05% had been excluded, the expense ratios would have been decreased by 2.38%, and the income ratios increased by 2.38%, for the year ended September 30, 2022. 9 If distribution and servicing fees of 0.25%, incentive fees of 1.64%, line of credit expenses of 0.13%, and other transaction related expenses of 0.06% had been excluded, the expense ratios would have been decreased by 2.08%, and the income ratios increased by 2.08% for the year ended September 30, 2021. 10 If distribution and servicing fees of 0.14%, incentive fees of 0.25%, and line of credit expenses of 0.29% had been excluded, the expense ratios would have been decreased by 0.68%, and the income ratios increased by 0.68%, for the period ended September 30, 2020. 11 Calculated at Fund level. | | | |
| General Description of Registrant [Abstract] | | | | | | | |
| Investment Objectives and Practices [Text Block] | | | | The Keystone Private Income Fund (the “Fund”) is a Delaware statutory trust registered under the Investment Company Act of 1940, as amended (the “Investment Company Act”), as a non -diversified -end The Fund offers five separate classes (each a “Class”) of shares of beneficial interest (“Shares”) designated as Class A, Class D, Class Y Class I, and Class Z Shares. As used herein, “Shareholders” refers to the holders of Shares of the Fund. Each class of Shares is subject to different fees and expenses. As of September 30, 2024, there were no Class A Shares of the Fund outstanding. The Fund may offer additional classes of Shares in the future. The Fund’s primary investment objective is to produce current income. The Investment Manager manages the Fund’s portfolio with a view toward producing current income, managing liquidity and protecting against downside scenarios. Under normal market conditions, the Fund will seek to achieve its investment objective by opportunistically investing, directly or indirectly, a majority of its net assets (plus any borrowings for investment purposes) in a wide range of private credit -oriented -producing | | | |
| Risk Factors [Table Text Block] | | | | Principal Risks Non-Diversified Status The Fund is a “non -diversified Limited Liquidity Shares in the Fund provide limited liquidity since Shareholders will not be able to redeem Shares on a daily basis. A Shareholder may not be able to tender its Shares in the Fund promptly after it has made a decision to do so. In addition, with very limited exceptions, Shares are not transferable, and liquidity will be provided only through repurchase offers made quarterly by the Fund. Shares in the Fund are therefore suitable only for investors who can bear the risks associated with the limited liquidity of Shares and should be viewed as a long -term Investment Manager Incentive Fee Risk Any Incentive Fee (defined below) payable by the Fund that relates to its net investment income may be computed and paid on income that may include interest or gains that have been accrued or are unrealized, but not yet received or realized. The Investment Manager is not under any obligation to reimburse the Fund for any part of the Incentive Fee it received that was based on accrued income or unrealized gains that the Fund never received or realized, and such circumstances would result in the Fund’s paying an Incentive Fee on income it never received or gains it never realized. The Incentive Fee payable by the Fund to the Investment Manager may create an incentive for it to make investments on the Fund’s behalf that are risky or more speculative than would be the case in the absence of such compensation arrangement. The way in which the Incentive Fee payable to the Investment Manager is determined may encourage it to use leverage to increase the return on the Fund’s investments. Under certain circumstances, the use of leverage may increase the likelihood of default, which would disfavor Shareholders. Such a practice could result in the Fund’s investing in more speculative securities than would otherwise be in its best interests, which could result in higher investment losses, particularly during cyclical economic downturns. Private Credit Private credit is a common term for unregistered debt investments made through privately negotiated transactions. Private credit investments may be structured using a range of financial instruments, including without limitation first and second lien senior secured loans, subordinated or unsecured debt and preferred equity arrangements. From time to time these investments might include equity features such as warrants, options, or common stock depending on the strategy of the investor and the financing requirements of the company or asset. Loans to private companies, businesses and operators can range in credit quality depending on security -specific Market Disruption and Geopolitical Risks Certain local, regional or global events such as war (including Russia’s invasion of Ukraine and the Israel -Hamas Banking Risk The impairment or failure of one or more banks with whom the Fund transacts may inhibit the Fund’s ability to access depository accounts. In the event of such a failure of a banking institution where the Fund holds depository accounts, access to such accounts could be restricted and U.S. Federal Deposit Insurance Corporation (“FDIC”) protection may not be available for balances in excess of amounts insured by the FDIC. In such instances, the Fund may not recover such excess, uninsured amounts. | | | |
| Effects of Leverage [Text Block] | | | | Borrowing, Use of Leverage The Fund may employ leverage through a secured Revolving Loan Agreement, as amended (the “Revolving Loan Agreement”) to achieve its investment objective. The Fund’s willingness to use leverage, and the extent to which leverage is used at any time, will depend on many factors, including the Investment Manager’s assessment of the yield curve environment, interest rate trends, market conditions and other factors. Borrowings by the Fund will further diminish returns (or increase losses on capital) to the extent overall returns are less than the Fund’s cost of funds. Such debt exposes the Fund to refinancing, recourse and other risks. As a general matter, the presence of leverage can accelerate losses. Subject to prevailing market conditions, the Fund may add financial leverage if, immediately after such borrowing, it would have asset coverage (as defined in the Investment Company Act) of 300% or more (in the event leverage is obtained solely through debt) or 200% or more (in the event leverage is obtained solely though preferred stock). The Fund may use leverage opportunistically and may choose to increase or decrease its leverage, or use different types or combinations of leveraging instruments, at any time based on the Fund’s assessment of market conditions and the investment environment. The Investment Manager expects that the Fund’s borrowings may ultimately be secured with a security interest in Fund investments. In times of adverse market conditions, the Fund may be required to post additional collateral which could affect the Fund’s liquidity. As of September 30, 2024, the Revolving Loan Agreement has maximum credit available of $275,000,000 with a maturity date of August 8.33%, respectively. For the year ended September 30, 2024, the Fund incurred and paid interest expense of $3,089,678, and $3,222,839, respectively. As of September 30, 2024, the Fund has an outstanding line of credit balance of $61,963,548 at a 8.05% interest rate. The maximum the Fund borrowed during the fiscal year ended September 30, 2024 was $94,120,000 on December 27, 2023. | | | |
| Non-Diversified Status [Member] | | | | | | | |
| General Description of Registrant [Abstract] | | | | | | | |
| Risk [Text Block] | | | | Non-Diversified Status The Fund is a “non -diversified | | | |
| Limited Liquidity [Member] | | | | | | | |
| General Description of Registrant [Abstract] | | | | | | | |
| Risk [Text Block] | | | | Limited Liquidity Shares in the Fund provide limited liquidity since Shareholders will not be able to redeem Shares on a daily basis. A Shareholder may not be able to tender its Shares in the Fund promptly after it has made a decision to do so. In addition, with very limited exceptions, Shares are not transferable, and liquidity will be provided only through repurchase offers made quarterly by the Fund. Shares in the Fund are therefore suitable only for investors who can bear the risks associated with the limited liquidity of Shares and should be viewed as a long -term | | | |
| Investment Manager Incentive Fee Risk [Member] | | | | | | | |
| General Description of Registrant [Abstract] | | | | | | | |
| Risk [Text Block] | | | | Investment Manager Incentive Fee Risk Any Incentive Fee (defined below) payable by the Fund that relates to its net investment income may be computed and paid on income that may include interest or gains that have been accrued or are unrealized, but not yet received or realized. The Investment Manager is not under any obligation to reimburse the Fund for any part of the Incentive Fee it received that was based on accrued income or unrealized gains that the Fund never received or realized, and such circumstances would result in the Fund’s paying an Incentive Fee on income it never received or gains it never realized. The Incentive Fee payable by the Fund to the Investment Manager may create an incentive for it to make investments on the Fund’s behalf that are risky or more speculative than would be the case in the absence of such compensation arrangement. The way in which the Incentive Fee payable to the Investment Manager is determined may encourage it to use leverage to increase the return on the Fund’s investments. Under certain circumstances, the use of leverage may increase the likelihood of default, which would disfavor Shareholders. Such a practice could result in the Fund’s investing in more speculative securities than would otherwise be in its best interests, which could result in higher investment losses, particularly during cyclical economic downturns. | | | |
| Private Credit [Member] | | | | | | | |
| General Description of Registrant [Abstract] | | | | | | | |
| Risk [Text Block] | | | | Private Credit Private credit is a common term for unregistered debt investments made through privately negotiated transactions. Private credit investments may be structured using a range of financial instruments, including without limitation first and second lien senior secured loans, subordinated or unsecured debt and preferred equity arrangements. From time to time these investments might include equity features such as warrants, options, or common stock depending on the strategy of the investor and the financing requirements of the company or asset. Loans to private companies, businesses and operators can range in credit quality depending on security -specific | | | |
| Market Disruption and Geopolitical Risks [Member] | | | | | | | |
| General Description of Registrant [Abstract] | | | | | | | |
| Risk [Text Block] | | | | Market Disruption and Geopolitical Risks Certain local, regional or global events such as war (including Russia’s invasion of Ukraine and the Israel -Hamas | | | |
| Banking Risk [Member] | | | | | | | |
| General Description of Registrant [Abstract] | | | | | | | |
| Risk [Text Block] | | | | Banking Risk The impairment or failure of one or more banks with whom the Fund transacts may inhibit the Fund’s ability to access depository accounts. In the event of such a failure of a banking institution where the Fund holds depository accounts, access to such accounts could be restricted and U.S. Federal Deposit Insurance Corporation (“FDIC”) protection may not be available for balances in excess of amounts insured by the FDIC. In such instances, the Fund may not recover such excess, uninsured amounts. | | | |
| Class D Shares [Member] | | | | | | | |
| Financial Highlights [Abstract] | | | | | | | |
| Senior Securities Amount | $ 5,000 | $ 5,000 | $ 5,000 | $ 61,964 | $ 60,659 | $ 64,926 | $ 29,433 |
| Senior Securities Average Market Value per Unit | $ 14,265 | | | $ 23,662 | $ 18,106 | $ 11,710 | $ 12,037 |
| Class Y Shares [Member] | | | | | | | |
| Financial Highlights [Abstract] | | | | | | | |
| Senior Securities Amount | $ 5,000 | 5,000 | $ 5,000 | $ 61,964 | $ 60,659 | $ 64,926 | $ 29,433 |
| Senior Securities Average Market Value per Unit | | | $ 14,265 | $ 23,662 | $ 18,106 | $ 11,710 | $ 12,037 |
| Class I Shares [Member] | | | | | | | |
| Financial Highlights [Abstract] | | | | | | | |
| Senior Securities Amount | 5,000 | $ 5,000 | $ 5,000 | $ 61,964 | $ 60,659 | $ 64,926 | $ 29,433 |
| Senior Securities Average Market Value per Unit | | $ 14,265 | | $ 23,662 | $ 18,106 | $ 11,710 | $ 12,037 |
| Class Z Shares [Member] | | | | | | | |
| Financial Highlights [Abstract] | | | | | | | |
| Senior Securities Amount | $ 5,000 | $ 5,000 | $ 5,000 | $ 61,964 | $ 60,659 | $ 64,926 | $ 29,433 |
| Senior Securities Average Market Value per Unit | | $ 14,265 | | $ 23,662 | $ 18,106 | $ 11,710 | $ 12,037 |
