3.26.1 html 3082 570 1 true 627 0 false 14 false false R1.htm 0000001 - Document - Cover Sheet http://www.prospectstreet.com/role/Cover Cover Cover 1 false false R2.htm 0000002 - Document - Audit Information Sheet http://www.prospectstreet.com/role/AuditInformation Audit Information Cover 2 false false R3.htm 0000003 - Statement - CONSOLIDATED STATEMENTS OF ASSETS AND LIABILITIES Sheet http://www.prospectstreet.com/role/CONSOLIDATEDSTATEMENTSOFASSETSANDLIABILITIES CONSOLIDATED STATEMENTS OF ASSETS AND LIABILITIES Statements 3 false false R4.htm 0000004 - Statement - CONSOLIDATED STATEMENTS OF ASSETS AND LIABILITIES (Parenthetical) Sheet http://www.prospectstreet.com/role/CONSOLIDATEDSTATEMENTSOFASSETSANDLIABILITIESParenthetical CONSOLIDATED STATEMENTS OF ASSETS AND LIABILITIES (Parenthetical) Statements 4 false false R5.htm 0000005 - Statement - CONSOLIDATED STATEMENTS OF OPERATIONS Sheet http://www.prospectstreet.com/role/CONSOLIDATEDSTATEMENTSOFOPERATIONS CONSOLIDATED STATEMENTS OF OPERATIONS Statements 5 false false R6.htm 0000006 - Statement - CONSOLIDATED STATEMENTS OF OTHER COMPREHENSIVE INCOME Sheet http://www.prospectstreet.com/role/CONSOLIDATEDSTATEMENTSOFOTHERCOMPREHENSIVEINCOME CONSOLIDATED STATEMENTS OF OTHER COMPREHENSIVE INCOME Statements 6 false false R7.htm 0000007 - Statement - CONSOLIDATED STATEMENTS OF CHANGES IN NET ASSETS AND TEMPORARY EQUITY Sheet http://www.prospectstreet.com/role/CONSOLIDATEDSTATEMENTSOFCHANGESINNETASSETSANDTEMPORARYEQUITY CONSOLIDATED STATEMENTS OF CHANGES IN NET ASSETS AND TEMPORARY EQUITY Statements 7 false false R8.htm 0000008 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS Sheet http://www.prospectstreet.com/role/CONSOLIDATEDSTATEMENTSOFCASHFLOWS CONSOLIDATED STATEMENTS OF CASH FLOWS Statements 8 false false R9.htm 0000009 - Statement - CONSOLIDATED SCHEDULE OF INVESTMENTS Sheet http://www.prospectstreet.com/role/CONSOLIDATEDSCHEDULEOFINVESTMENTS CONSOLIDATED SCHEDULE OF INVESTMENTS Statements 9 false false R10.htm 0000010 - Statement - CONSOLIDATED SCHEDULE OF INVESTMENTS (Parenthetical) 1 Sheet http://www.prospectstreet.com/role/CONSOLIDATEDSCHEDULEOFINVESTMENTSParenthetical1 CONSOLIDATED SCHEDULE OF INVESTMENTS (Parenthetical) 1 Statements 10 false false R11.htm 0000011 - Statement - CONSOLIDATED SCHEDULE OF INVESTMENTS (Parenthetical) 2 Sheet http://www.prospectstreet.com/role/CONSOLIDATEDSCHEDULEOFINVESTMENTSParenthetical2 CONSOLIDATED SCHEDULE OF INVESTMENTS (Parenthetical) 2 Statements 11 false false R12.htm 0000012 - Statement - CONSOLIDATED SCHEDULE OF INVESTMENTS (Parenthetical) 3 Sheet http://www.prospectstreet.com/role/CONSOLIDATEDSCHEDULEOFINVESTMENTSParenthetical3 CONSOLIDATED SCHEDULE OF INVESTMENTS (Parenthetical) 3 Statements 12 false false R13.htm 0000013 - Statement - CONSOLIDATED SCHEDULE OF INVESTMENTS (Parenthetical) 4 Sheet http://www.prospectstreet.com/role/CONSOLIDATEDSCHEDULEOFINVESTMENTSParenthetical4 CONSOLIDATED SCHEDULE OF INVESTMENTS (Parenthetical) 4 Statements 13 false false R14.htm 0000014 - Statement - CONSOLIDATED SCHEDULE OF INVESTMENTS (Parenthetical) 5 Sheet http://www.prospectstreet.com/role/CONSOLIDATEDSCHEDULEOFINVESTMENTSParenthetical5 CONSOLIDATED SCHEDULE OF INVESTMENTS (Parenthetical) 5 Statements 14 false false R15.htm 0000015 - Statement - CONSOLIDATED SCHEDULE OF INVESTMENTS (Parenthetical) 6 Sheet http://www.prospectstreet.com/role/CONSOLIDATEDSCHEDULEOFINVESTMENTSParenthetical6 CONSOLIDATED SCHEDULE OF INVESTMENTS (Parenthetical) 6 Statements 15 false false R16.htm 0000016 - Statement - CONSOLIDATED SCHEDULE OF INVESTMENTS (Parenthetical) 7 Sheet http://www.prospectstreet.com/role/CONSOLIDATEDSCHEDULEOFINVESTMENTSParenthetical7 CONSOLIDATED SCHEDULE OF INVESTMENTS (Parenthetical) 7 Statements 16 false false R17.htm 0000017 - Statement - CONSOLIDATED SCHEDULE OF INVESTMENTS (Parenthetical) 8 Sheet http://www.prospectstreet.com/role/CONSOLIDATEDSCHEDULEOFINVESTMENTSParenthetical8 CONSOLIDATED SCHEDULE OF INVESTMENTS (Parenthetical) 8 Statements 17 false false R18.htm 0000018 - Statement - CONSOLIDATED SCHEDULE OF INVESTMENTS (Parenthetical) 9 Sheet http://www.prospectstreet.com/role/CONSOLIDATEDSCHEDULEOFINVESTMENTSParenthetical9 CONSOLIDATED SCHEDULE OF INVESTMENTS (Parenthetical) 9 Statements 18 false false R19.htm 0000019 - Statement - CONSOLIDATED SCHEDULE OF INVESTMENTS (Parenthetical) 10 Sheet http://www.prospectstreet.com/role/CONSOLIDATEDSCHEDULEOFINVESTMENTSParenthetical10 CONSOLIDATED SCHEDULE OF INVESTMENTS (Parenthetical) 10 Statements 19 false false R20.htm 0000020 - Statement - CONSOLIDATED SCHEDULE OF INVESTMENTS (Parenthetical) 10 Sheet http://www.prospectstreet.com/role/CONSOLIDATEDSCHEDULEOFINVESTMENTSParenthetical10_2 CONSOLIDATED SCHEDULE OF INVESTMENTS (Parenthetical) 10 Statements 20 false false R21.htm 0000021 - Statement - CONSOLIDATED SCHEDULE OF INVESTMENTS (Parenthetical) 11 Sheet http://www.prospectstreet.com/role/CONSOLIDATEDSCHEDULEOFINVESTMENTSParenthetical11 CONSOLIDATED SCHEDULE OF INVESTMENTS (Parenthetical) 11 Statements 21 false false R22.htm 0000022 - Statement - CONSOLIDATED SCHEDULES OF INVESTMENTS (Parenthetical) 3 Sheet http://www.prospectstreet.com/role/CONSOLIDATEDSCHEDULESOFINVESTMENTSParenthetical3 CONSOLIDATED SCHEDULES OF INVESTMENTS (Parenthetical) 3 Statements 22 false false R23.htm 0000023 - Statement - CONSOLIDATED SCHEDULES OF INVESTMENTS (Parenthetical) Sheet http://www.prospectstreet.com/role/CONSOLIDATEDSCHEDULESOFINVESTMENTSParenthetical CONSOLIDATED SCHEDULES OF INVESTMENTS (Parenthetical) Statements 23 false false R24.htm 0000024 - Statement - CONSOLIDATED SCHEDULES OF INVESTMENTS (Parenthetical) 4 Sheet http://www.prospectstreet.com/role/CONSOLIDATEDSCHEDULESOFINVESTMENTSParenthetical4 CONSOLIDATED SCHEDULES OF INVESTMENTS (Parenthetical) 4 Statements 24 false false R25.htm 0000025 - Statement - CONSOLIDATED SCHEDULES OF INVESTMENTS (Parenthetical) 5 Sheet http://www.prospectstreet.com/role/CONSOLIDATEDSCHEDULESOFINVESTMENTSParenthetical5 CONSOLIDATED SCHEDULES OF INVESTMENTS (Parenthetical) 5 Statements 25 false false R26.htm 0000026 - Statement - CONSOLIDATED SCHEDULES OF INVESTMENTS (Parenthetical) 6 Sheet http://www.prospectstreet.com/role/CONSOLIDATEDSCHEDULESOFINVESTMENTSParenthetical6 CONSOLIDATED SCHEDULES OF INVESTMENTS (Parenthetical) 6 Statements 26 false false R27.htm 0000027 - Statement - CONSOLIDATED SCHEDULES OF INVESTMENTS (Parenthetical) 7 Sheet http://www.prospectstreet.com/role/CONSOLIDATEDSCHEDULESOFINVESTMENTSParenthetical7 CONSOLIDATED SCHEDULES OF INVESTMENTS (Parenthetical) 7 Statements 27 false false R28.htm 0000028 - Statement - CONSOLIDATED SCHEDULES OF INVESTMENTS (Parenthetical) 8 Sheet http://www.prospectstreet.com/role/CONSOLIDATEDSCHEDULESOFINVESTMENTSParenthetical8 CONSOLIDATED SCHEDULES OF INVESTMENTS (Parenthetical) 8 Statements 28 false false R29.htm 0000029 - Disclosure - Organization Sheet http://www.prospectstreet.com/role/Organization Organization Notes 29 false false R30.htm 0000030 - Disclosure - Significant Accounting Policies Sheet http://www.prospectstreet.com/role/SignificantAccountingPolicies Significant Accounting Policies Notes 30 false false R31.htm 0000031 - Disclosure - Portfolio Investments Sheet http://www.prospectstreet.com/role/PortfolioInvestments Portfolio Investments Notes 31 false false R32.htm 0000032 - Disclosure - Revolving Credit Facility Sheet http://www.prospectstreet.com/role/RevolvingCreditFacility Revolving Credit Facility Notes 32 false false R33.htm 0000033 - Disclosure - Convertible Notes Notes http://www.prospectstreet.com/role/ConvertibleNotes Convertible Notes Notes 33 false false R34.htm 0000034 - Disclosure - Public Notes Notes http://www.prospectstreet.com/role/PublicNotes Public Notes Notes 34 false false R35.htm 0000035 - Disclosure - Prospect Capital InterNotes® Notes http://www.prospectstreet.com/role/ProspectCapitalInterNotes Prospect Capital InterNotes® Notes 35 false false R36.htm 0000036 - Disclosure - Fair Value and Maturity of Debt Outstanding Sheet http://www.prospectstreet.com/role/FairValueandMaturityofDebtOutstanding Fair Value and Maturity of Debt Outstanding Notes 36 false false R37.htm 0000037 - Disclosure - Equity Offerings, Offering Expenses, and Distributions Sheet http://www.prospectstreet.com/role/EquityOfferingsOfferingExpensesandDistributions Equity Offerings, Offering Expenses, and Distributions Notes 37 false false R38.htm 0000038 - Disclosure - Other Income Sheet http://www.prospectstreet.com/role/OtherIncome Other Income Notes 38 false false R39.htm 0000039 - Disclosure - Net Increase (Decrease) in Net Assets per Common Share Sheet http://www.prospectstreet.com/role/NetIncreaseDecreaseinNetAssetsperCommonShare Net Increase (Decrease) in Net Assets per Common Share Notes 39 false false R40.htm 0000040 - Disclosure - Income Taxes Sheet http://www.prospectstreet.com/role/IncomeTaxes Income Taxes Notes 40 false false R41.htm 0000041 - Disclosure - Related Party Agreements and Transactions Sheet http://www.prospectstreet.com/role/RelatedPartyAgreementsandTransactions Related Party Agreements and Transactions Notes 41 false false R42.htm 0000042 - Disclosure - Transactions with Controlled Companies Sheet http://www.prospectstreet.com/role/TransactionswithControlledCompanies Transactions with Controlled Companies Notes 42 false false R43.htm 0000043 - Disclosure - Litigation Sheet http://www.prospectstreet.com/role/Litigation Litigation Notes 43 false false R44.htm 0000044 - Disclosure - Financial Highlights Sheet http://www.prospectstreet.com/role/FinancialHighlights Financial Highlights Notes 44 false false R45.htm 0000045 - Disclosure - Segment Reporting Sheet http://www.prospectstreet.com/role/SegmentReporting Segment Reporting Notes 45 false false R46.htm 0000046 - Disclosure - Subsequent Events Sheet http://www.prospectstreet.com/role/SubsequentEvents Subsequent Events Notes 46 false false R47.htm 995445 - Disclosure - Insider Trading Arrangements Sheet http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements Insider Trading Arrangements Notes 47 false false R48.htm 995447 - Disclosure - Insider Trading Policies and Procedures Sheet http://xbrl.sec.gov/ecd/role/InsiderTradingPoliciesProc Insider Trading Policies and Procedures Notes 48 false false R49.htm 995470 - Disclosure - N-2 Sheet http://xbrl.sec.gov/cef/role/N2 N-2 Notes 49 false false R50.htm 995550 - Disclosure - Cybersecurity Risk Management and Strategy Disclosure Sheet http://xbrl.sec.gov/cyd/role/CybersecurityRiskManagementAndStrategyDisclosure Cybersecurity Risk Management and Strategy Disclosure Notes 50 false false R51.htm 9955511 - Disclosure - Significant Accounting Policies (Policies) Sheet http://www.prospectstreet.com/role/SignificantAccountingPoliciesPolicies Significant Accounting Policies (Policies) Policies http://www.prospectstreet.com/role/SignificantAccountingPolicies 51 false false R52.htm 9955512 - Disclosure - Portfolio Investments (Tables) Sheet http://www.prospectstreet.com/role/PortfolioInvestmentsTables Portfolio Investments (Tables) Tables http://www.prospectstreet.com/role/PortfolioInvestments 52 false false R53.htm 9955513 - Disclosure - Revolving Credit Facility (Tables) Sheet http://www.prospectstreet.com/role/RevolvingCreditFacilityTables Revolving Credit Facility (Tables) Tables http://www.prospectstreet.com/role/RevolvingCreditFacility 53 false false R54.htm 9955514 - Disclosure - Public Notes (Tables) Notes http://www.prospectstreet.com/role/PublicNotesTables Public Notes (Tables) Tables http://www.prospectstreet.com/role/PublicNotes 54 false false R55.htm 9955515 - Disclosure - Prospect Capital InterNotes® (Tables) Notes http://www.prospectstreet.com/role/ProspectCapitalInterNotesTables Prospect Capital InterNotes® (Tables) Tables http://www.prospectstreet.com/role/ProspectCapitalInterNotes 55 false false R56.htm 9955516 - Disclosure - Fair Value and Maturity of Debt Outstanding (Tables) Sheet http://www.prospectstreet.com/role/FairValueandMaturityofDebtOutstandingTables Fair Value and Maturity of Debt Outstanding (Tables) Tables http://www.prospectstreet.com/role/FairValueandMaturityofDebtOutstanding 56 false false R57.htm 9955517 - Disclosure - Equity Offerings, Offering Expenses, and Distributions (Tables) Sheet http://www.prospectstreet.com/role/EquityOfferingsOfferingExpensesandDistributionsTables Equity Offerings, Offering Expenses, and Distributions (Tables) Tables http://www.prospectstreet.com/role/EquityOfferingsOfferingExpensesandDistributions 57 false false R58.htm 9955518 - Disclosure - Other Income (Tables) Sheet http://www.prospectstreet.com/role/OtherIncomeTables Other Income (Tables) Tables http://www.prospectstreet.com/role/OtherIncome 58 false false R59.htm 9955519 - Disclosure - Net Increase (Decrease) in Net Assets per Common Share (Tables) Sheet http://www.prospectstreet.com/role/NetIncreaseDecreaseinNetAssetsperCommonShareTables Net Increase (Decrease) in Net Assets per Common Share (Tables) Tables http://www.prospectstreet.com/role/NetIncreaseDecreaseinNetAssetsperCommonShare 59 false false R60.htm 9955520 - Disclosure - Income Taxes (Tables) Sheet http://www.prospectstreet.com/role/IncomeTaxesTables Income Taxes (Tables) Tables http://www.prospectstreet.com/role/IncomeTaxes 60 false false R61.htm 9955521 - Disclosure - Transactions with Controlled Companies (Tables) Sheet http://www.prospectstreet.com/role/TransactionswithControlledCompaniesTables Transactions with Controlled Companies (Tables) Tables http://www.prospectstreet.com/role/TransactionswithControlledCompanies 61 false false R62.htm 9955522 - Disclosure - Financial Highlights (Tables) Sheet http://www.prospectstreet.com/role/FinancialHighlightsTables Financial Highlights (Tables) Tables http://www.prospectstreet.com/role/FinancialHighlights 62 false false R63.htm 9955523 - Disclosure - Subsequent Events (Tables) Sheet http://www.prospectstreet.com/role/SubsequentEventsTables Subsequent Events (Tables) Tables http://www.prospectstreet.com/role/SubsequentEvents 63 false false R64.htm 9955524 - Disclosure - Significant Accounting Policies (Details) Sheet http://www.prospectstreet.com/role/SignificantAccountingPoliciesDetails Significant Accounting Policies (Details) Details http://www.prospectstreet.com/role/SignificantAccountingPoliciesPolicies 64 false false R65.htm 9955525 - Disclosure - Portfolio Investments - Narrative (Details) Sheet http://www.prospectstreet.com/role/PortfolioInvestmentsNarrativeDetails Portfolio Investments - Narrative (Details) Details 65 false false R66.htm 9955526 - Disclosure - Portfolio Investments - Composition of Investment Portfolio (Details) Sheet http://www.prospectstreet.com/role/PortfolioInvestmentsCompositionofInvestmentPortfolioDetails Portfolio Investments - Composition of Investment Portfolio (Details) Details 66 false false R67.htm 9955527 - Disclosure - Portfolio Investments - Fair Value of Investments (Details) Sheet http://www.prospectstreet.com/role/PortfolioInvestmentsFairValueofInvestmentsDetails Portfolio Investments - Fair Value of Investments (Details) Details 67 false false R68.htm 9955528 - Disclosure - Portfolio Investments - Changes in Fair Value of Level 3 Investments (Details) Sheet http://www.prospectstreet.com/role/PortfolioInvestmentsChangesinFairValueofLevel3InvestmentsDetails Portfolio Investments - Changes in Fair Value of Level 3 Investments (Details) Details 68 false false R69.htm 9955529 - Disclosure - Portfolio Investments - Industries and Geographical Locations Comprising Greater than 10% of Portfolio Fair Value (Details) Sheet http://www.prospectstreet.com/role/PortfolioInvestmentsIndustriesandGeographicalLocationsComprisingGreaterthan10ofPortfolioFairValueDetails Portfolio Investments - Industries and Geographical Locations Comprising Greater than 10% of Portfolio Fair Value (Details) Details 69 false false R70.htm 9955530 - Disclosure - Portfolio Investments - Unobservable Inputs Used in Fair Value Measurement of Level 3 Investments (Details) Sheet http://www.prospectstreet.com/role/PortfolioInvestmentsUnobservableInputsUsedinFairValueMeasurementofLevel3InvestmentsDetails Portfolio Investments - Unobservable Inputs Used in Fair Value Measurement of Level 3 Investments (Details) Details 70 false false R71.htm 9955531 - Disclosure - Portfolio Investments - Mortgages Outstanding for NPRC (Details) Sheet http://www.prospectstreet.com/role/PortfolioInvestmentsMortgagesOutstandingforNPRCDetails Portfolio Investments - Mortgages Outstanding for NPRC (Details) Details 71 false false R72.htm 9955532 - Disclosure - Portfolio Investments - Unconsolidated Significant Subsidiaries (Details) Sheet http://www.prospectstreet.com/role/PortfolioInvestmentsUnconsolidatedSignificantSubsidiariesDetails Portfolio Investments - Unconsolidated Significant Subsidiaries (Details) Details 72 false false R73.htm 9955533 - Disclosure - Revolving Credit Facility - Narrative (Details) Sheet http://www.prospectstreet.com/role/RevolvingCreditFacilityNarrativeDetails Revolving Credit Facility - Narrative (Details) Details 73 false false R74.htm 9955534 - Disclosure - Revolving Credit Facility - Schedule of Average Rate and Outstanding Balance (Details) Sheet http://www.prospectstreet.com/role/RevolvingCreditFacilityScheduleofAverageRateandOutstandingBalanceDetails Revolving Credit Facility - Schedule of Average Rate and Outstanding Balance (Details) Details 74 false false R75.htm 9955535 - Disclosure - Convertible Notes (Details) Notes http://www.prospectstreet.com/role/ConvertibleNotesDetails Convertible Notes (Details) Details http://www.prospectstreet.com/role/ConvertibleNotes 75 false false R76.htm 9955536 - Disclosure - Public Notes - Narrative (Details) Notes http://www.prospectstreet.com/role/PublicNotesNarrativeDetails Public Notes - Narrative (Details) Details 76 false false R77.htm 9955537 - Disclosure - Public Notes - Schedule of Fair Value Amounts for the Company's Derivative Instruments (Details) Notes http://www.prospectstreet.com/role/PublicNotesScheduleofFairValueAmountsfortheCompanysDerivativeInstrumentsDetails Public Notes - Schedule of Fair Value Amounts for the Company's Derivative Instruments (Details) Details 77 false false R78.htm 9955538 - Disclosure - Public Notes - Schedule of Changes in the Fair Values of Derivatives Designated as Fair Value hedges on Earnings and Reclassification of Derivatives Designated as Cash Flow Hedges into Earnings (Details) Notes http://www.prospectstreet.com/role/PublicNotesScheduleofChangesintheFairValuesofDerivativesDesignatedasFairValuehedgesonEarningsandReclassificationofDerivativesDesignatedasCashFlowHedgesintoEarningsDetails Public Notes - Schedule of Changes in the Fair Values of Derivatives Designated as Fair Value hedges on Earnings and Reclassification of Derivatives Designated as Cash Flow Hedges into Earnings (Details) Details 78 false false R79.htm 9955539 - Disclosure - Public Notes - Schedule of Offsetting of Derivative Instruments (Details) (Details) Notes http://www.prospectstreet.com/role/PublicNotesScheduleofOffsettingofDerivativeInstrumentsDetailsDetails Public Notes - Schedule of Offsetting of Derivative Instruments (Details) (Details) Details 79 false false R80.htm 9955540 - Disclosure - Prospect Capital InterNotes® - Narrative (Details) Notes http://www.prospectstreet.com/role/ProspectCapitalInterNotesNarrativeDetails Prospect Capital InterNotes® - Narrative (Details) Details 80 false false R81.htm 9955541 - Disclosure - Prospect Capital InterNotes® - Schedule Issued Notes (Details) Notes http://www.prospectstreet.com/role/ProspectCapitalInterNotesScheduleIssuedNotesDetails Prospect Capital InterNotes® - Schedule Issued Notes (Details) Details 81 false false R82.htm 9955542 - Disclosure - Prospect Capital InterNotes® - Schedule of Notes Outstanding (Details) Notes http://www.prospectstreet.com/role/ProspectCapitalInterNotesScheduleofNotesOutstandingDetails Prospect Capital InterNotes® - Schedule of Notes Outstanding (Details) Details 82 false false R83.htm 9955543 - Disclosure - Fair Value and Maturity of Debt Outstanding - Narrative (Details) Sheet http://www.prospectstreet.com/role/FairValueandMaturityofDebtOutstandingNarrativeDetails Fair Value and Maturity of Debt Outstanding - Narrative (Details) Details 83 false false R84.htm 9955544 - Disclosure - Fair Value and Maturity of Debt Outstanding - Schedule Senior Securities (Details) Sheet http://www.prospectstreet.com/role/FairValueandMaturityofDebtOutstandingScheduleSeniorSecuritiesDetails Fair Value and Maturity of Debt Outstanding - Schedule Senior Securities (Details) Details 84 false false R85.htm 9955545 - Disclosure - Fair Value and Maturity of Debt Outstanding - Schedule of Carrying Values and Estimated Fair Values of Debt Instruments (Details) Sheet http://www.prospectstreet.com/role/FairValueandMaturityofDebtOutstandingScheduleofCarryingValuesandEstimatedFairValuesofDebtInstrumentsDetails Fair Value and Maturity of Debt Outstanding - Schedule of Carrying Values and Estimated Fair Values of Debt Instruments (Details) Details 85 false false R86.htm 9955546 - Disclosure - Fair Value and Maturity of Debt Outstanding - Schedule of Debt Maturity (Details) Sheet http://www.prospectstreet.com/role/FairValueandMaturityofDebtOutstandingScheduleofDebtMaturityDetails Fair Value and Maturity of Debt Outstanding - Schedule of Debt Maturity (Details) Details 86 false false R87.htm 9955547 - Disclosure - Equity Offerings, Offering Expenses, and Distributions - Preferred Stock Narrative (Details) Sheet http://www.prospectstreet.com/role/EquityOfferingsOfferingExpensesandDistributionsPreferredStockNarrativeDetails Equity Offerings, Offering Expenses, and Distributions - Preferred Stock Narrative (Details) Details 87 false false R88.htm 9955548 - Disclosure - Equity Offerings, Offering Expenses, and Distributions - Schedule of Preferred Stock Dividends (Details) Sheet http://www.prospectstreet.com/role/EquityOfferingsOfferingExpensesandDistributionsScheduleofPreferredStockDividendsDetails Equity Offerings, Offering Expenses, and Distributions - Schedule of Preferred Stock Dividends (Details) Details 88 false false R89.htm 9955549 - Disclosure - Equity Offerings, Offering Expenses, and Distributions - Schedule of Outstanding Preferred Shares (Details) Sheet http://www.prospectstreet.com/role/EquityOfferingsOfferingExpensesandDistributionsScheduleofOutstandingPreferredSharesDetails Equity Offerings, Offering Expenses, and Distributions - Schedule of Outstanding Preferred Shares (Details) Details 89 false false R90.htm 9955550 - Disclosure - Equity Offerings, Offering Expenses, and Distributions - Schedule of Outstanding Preferred Shares Activity (Details) Sheet http://www.prospectstreet.com/role/EquityOfferingsOfferingExpensesandDistributionsScheduleofOutstandingPreferredSharesActivityDetails Equity Offerings, Offering Expenses, and Distributions - Schedule of Outstanding Preferred Shares Activity (Details) Details 90 false false R91.htm 9955551 - Disclosure - Equity Offerings, Offering Expenses, and Distributions - Common Stock Narrative (Details) Sheet http://www.prospectstreet.com/role/EquityOfferingsOfferingExpensesandDistributionsCommonStockNarrativeDetails Equity Offerings, Offering Expenses, and Distributions - Common Stock Narrative (Details) Details 91 false false R92.htm 9955552 - Disclosure - Equity Offerings, Offering Expenses, and Distributions - Schedule of Common Stock Dividends (Details) Sheet http://www.prospectstreet.com/role/EquityOfferingsOfferingExpensesandDistributionsScheduleofCommonStockDividendsDetails Equity Offerings, Offering Expenses, and Distributions - Schedule of Common Stock Dividends (Details) Details 92 false false R93.htm 9955553 - Disclosure - Other Income (Details) Sheet http://www.prospectstreet.com/role/OtherIncomeDetails Other Income (Details) Details http://www.prospectstreet.com/role/OtherIncomeTables 93 false false R94.htm 9955554 - Disclosure - Net Increase (Decrease) in Net Assets per Common Share - Narrative (Details) Sheet http://www.prospectstreet.com/role/NetIncreaseDecreaseinNetAssetsperCommonShareNarrativeDetails Net Increase (Decrease) in Net Assets per Common Share - Narrative (Details) Details http://www.prospectstreet.com/role/NetIncreaseDecreaseinNetAssetsperCommonShareTables 94 false false R95.htm 9955555 - Disclosure - Net Increase (Decrease) in Net Assets per Common Share- Schedule of Computation of Basic and Diluted Earnings Per Common Share (Details) Sheet http://www.prospectstreet.com/role/NetIncreaseDecreaseinNetAssetsperCommonShareScheduleofComputationofBasicandDilutedEarningsPerCommonShareDetails Net Increase (Decrease) in Net Assets per Common Share- Schedule of Computation of Basic and Diluted Earnings Per Common Share (Details) Details http://www.prospectstreet.com/role/NetIncreaseDecreaseinNetAssetsperCommonShareTables 95 false false R96.htm 9955556 - Disclosure - Income Taxes - Schedule of Investment Company, Distribution to Shareholders (Details) Sheet http://www.prospectstreet.com/role/IncomeTaxesScheduleofInvestmentCompanyDistributiontoShareholdersDetails Income Taxes - Schedule of Investment Company, Distribution to Shareholders (Details) Details 96 false false R97.htm 9955557 - Disclosure - Income Taxes - Narrative (Details) Sheet http://www.prospectstreet.com/role/IncomeTaxesNarrativeDetails Income Taxes - Narrative (Details) Details 97 false false R98.htm 9955558 - Disclosure - Income Taxes - Schedule of Reconciliation of Net Increase in Net Assets Resulting from Operations to Taxable Income (Details) Sheet http://www.prospectstreet.com/role/IncomeTaxesScheduleofReconciliationofNetIncreaseinNetAssetsResultingfromOperationstoTaxableIncomeDetails Income Taxes - Schedule of Reconciliation of Net Increase in Net Assets Resulting from Operations to Taxable Income (Details) Details 98 false false R99.htm 9955559 - Disclosure - Related Party Agreements and Transactions (Details) Sheet http://www.prospectstreet.com/role/RelatedPartyAgreementsandTransactionsDetails Related Party Agreements and Transactions (Details) Details http://www.prospectstreet.com/role/RelatedPartyAgreementsandTransactions 99 false false R100.htm 9955560 - Disclosure - Transactions with Controlled Companies - Belnick, LLC (Details) Sheet http://www.prospectstreet.com/role/TransactionswithControlledCompaniesBelnickLLCDetails Transactions with Controlled Companies - Belnick, LLC (Details) Details 100 false false R101.htm 9955561 - Disclosure - Transactions with Controlled Companies - CP Energy Services Inc. (Details) Sheet http://www.prospectstreet.com/role/TransactionswithControlledCompaniesCPEnergyServicesIncDetails Transactions with Controlled Companies - CP Energy Services Inc. (Details) Details 101 false false R102.htm 9955562 - Disclosure - Transactions with Controlled Companies - Credit Central Loan Company, LLC (Details) Sheet http://www.prospectstreet.com/role/TransactionswithControlledCompaniesCreditCentralLoanCompanyLLCDetails Transactions with Controlled Companies - Credit Central Loan Company, LLC (Details) Details 102 false false R103.htm 9955563 - Disclosure - Transactions with Controlled Companies - Echelon Transportation LLC (Details) Sheet http://www.prospectstreet.com/role/TransactionswithControlledCompaniesEchelonTransportationLLCDetails Transactions with Controlled Companies - Echelon Transportation LLC (Details) Details 103 false false R104.htm 9955564 - Disclosure - Transactions with Controlled Companies - Energy Solutions Holdings Inc. (Details) Sheet http://www.prospectstreet.com/role/TransactionswithControlledCompaniesEnergySolutionsHoldingsIncDetails Transactions with Controlled Companies - Energy Solutions Holdings Inc. (Details) Details 104 false false R105.htm 9955565 - Disclosure - Transactions with Controlled Companies - First Tower Finance Company LLC (Details) Sheet http://www.prospectstreet.com/role/TransactionswithControlledCompaniesFirstTowerFinanceCompanyLLCDetails Transactions with Controlled Companies - First Tower Finance Company LLC (Details) Details 105 false false R106.htm 9955566 - Disclosure - Transactions with Controlled Companies - Freedom Marine Solutions, LLC (Details) Sheet http://www.prospectstreet.com/role/TransactionswithControlledCompaniesFreedomMarineSolutionsLLCDetails Transactions with Controlled Companies - Freedom Marine Solutions, LLC (Details) Details 106 false false R107.htm 9955567 - Disclosure - Transactions with Controlled Companies - InterDent, Inc. (Details) Sheet http://www.prospectstreet.com/role/TransactionswithControlledCompaniesInterDentIncDetails Transactions with Controlled Companies - InterDent, Inc. (Details) Details 107 false false R108.htm 9955568 - Disclosure - Transactions with Controlled Companies - Kickapoo Ranch Pet Resort (Details) Sheet http://www.prospectstreet.com/role/TransactionswithControlledCompaniesKickapooRanchPetResortDetails Transactions with Controlled Companies - Kickapoo Ranch Pet Resort (Details) Details 108 false false R109.htm 9955569 - Disclosure - Transactions with Controlled Companies - MITY, Inc. (Details) Sheet http://www.prospectstreet.com/role/TransactionswithControlledCompaniesMITYIncDetails Transactions with Controlled Companies - MITY, Inc. (Details) Details 109 false false R110.htm 9955570 - Disclosure - Transactions with Controlled Companies - National Property REIT Corp. (Details) Sheet http://www.prospectstreet.com/role/TransactionswithControlledCompaniesNationalPropertyREITCorpDetails Transactions with Controlled Companies - National Property REIT Corp. (Details) Details 110 false false R111.htm 9955571 - Disclosure - Transactions with Controlled Companies - Nationwide Loan Company LLC (Details) Sheet http://www.prospectstreet.com/role/TransactionswithControlledCompaniesNationwideLoanCompanyLLCDetails Transactions with Controlled Companies - Nationwide Loan Company LLC (Details) Details 111 false false R112.htm 9955572 - Disclosure - Transactions with Controlled Companies - NMMB, Inc. (Details) Sheet http://www.prospectstreet.com/role/TransactionswithControlledCompaniesNMMBIncDetails Transactions with Controlled Companies - NMMB, Inc. (Details) Details 112 false false R113.htm 9955573 - Disclosure - Transactions with Controlled Companies - Pacific World Corporation (Details) Sheet http://www.prospectstreet.com/role/TransactionswithControlledCompaniesPacificWorldCorporationDetails Transactions with Controlled Companies - Pacific World Corporation (Details) Details 113 false false R114.htm 9955574 - Disclosure - Transactions with Controlled Companies - QC Holdings TopCo, LLC (Details) Sheet http://www.prospectstreet.com/role/TransactionswithControlledCompaniesQCHoldingsTopCoLLCDetails Transactions with Controlled Companies - QC Holdings TopCo, LLC (Details) Details 114 false false R115.htm 9955575 - Disclosure - Transactions with Controlled Companies - R-V Industries, Inc. (Details) Sheet http://www.prospectstreet.com/role/TransactionswithControlledCompaniesRVIndustriesIncDetails Transactions with Controlled Companies - R-V Industries, Inc. (Details) Details 115 false false R116.htm 9955576 - Disclosure - Transactions with Controlled Companies - Strategic Chemical Solutions Corp. (Details) Sheet http://www.prospectstreet.com/role/TransactionswithControlledCompaniesStrategicChemicalSolutionsCorpDetails Transactions with Controlled Companies - Strategic Chemical Solutions Corp. (Details) Details 116 false false R117.htm 9955577 - Disclosure - Transactions with Controlled Companies - Universal Turbine Parts, LLC (Details) Sheet http://www.prospectstreet.com/role/TransactionswithControlledCompaniesUniversalTurbinePartsLLCDetails Transactions with Controlled Companies - Universal Turbine Parts, LLC (Details) Details 117 false false R118.htm 9955578 - Disclosure - Transactions with Controlled Companies - Valley Electric Company, Inc. (Details) Sheet http://www.prospectstreet.com/role/TransactionswithControlledCompaniesValleyElectricCompanyIncDetails Transactions with Controlled Companies - Valley Electric Company, Inc. (Details) Details 118 false false R119.htm 9955579 - Disclosure - Transactions with Controlled Companies - Victor Technology, LLC (Details) Sheet http://www.prospectstreet.com/role/TransactionswithControlledCompaniesVictorTechnologyLLCDetails Transactions with Controlled Companies - Victor Technology, LLC (Details) Details 119 false false R120.htm 9955580 - Disclosure - Financial Highlights (Details) Sheet http://www.prospectstreet.com/role/FinancialHighlightsDetails Financial Highlights (Details) Details http://www.prospectstreet.com/role/FinancialHighlightsTables 120 false false R121.htm 9955581 - Disclosure - Segment Reporting (Details) Sheet http://www.prospectstreet.com/role/SegmentReportingDetails Segment Reporting (Details) Details http://www.prospectstreet.com/role/SegmentReporting 121 false false R122.htm 9955582 - Disclosure - Subsequent Events (Details) Sheet http://www.prospectstreet.com/role/SubsequentEventsDetails Subsequent Events (Details) Details http://www.prospectstreet.com/role/SubsequentEventsTables 122 false false All Reports Book All Reports psec-20260630.htm psec-20260630.xsd psec-20260630_cal.xml psec-20260630_def.xml psec-20260630_lab.xml psec-20260630_pre.xml psec-20260630_g1.jpg http://fasb.org/srt/2026 http://fasb.org/us-gaap/2026 http://xbrl.sec.gov/cef/2026 http://xbrl.sec.gov/cyd/2026 http://xbrl.sec.gov/dei/2026 http://xbrl.sec.gov/ecd/2026 true true