Trading Arrangements, by Individual Trading Arrangements, by Individual [Table] Trading Arrangement: Trading Arrangement [Axis] Maximum Maximum [Member] NPH Property Holdings, LLC NPH Property Holdings, LLC [Member] NPH Property Holdings, LLC Spartan Energy Holdings, Inc. Spartan Energy Holdings, Inc. [Member] Spartan Energy Holdings, Inc. Common Equity/Interests/Warrants 7 Common Stock, Interests Or Warrants7 [Member] Common Stock, Interests Or Warrants7 Title of 12(b) Security Subsequent Event Subsequent Event [Member] Net increase (decrease) in net assets resulting from operations - diluted Net Income (Loss) Available to Common Stockholders, Diluted Weighted average interest rate Weighted Average Interest Rate Debt, Weighted Average Interest Rate Adjustment to Compensation, Amount Adjustment to Compensation Amount Financial Instrument [Axis] Financial Instrument [Axis] Fully diluted ownership interest Fully Diluted, Ownership Fully Diluted, Ownership Segment Reporting [Abstract] Schedule of Fair Value of Investments Fair Value, Assets Measured on Recurring Basis [Table Text Block] To Offset Current Period Allocations of Overhead Expense, Reimbursement Of Administration Expense To Offset Current Period Allocations of Overhead Expense, Reimbursement Of Administration Expense [Member] To Offset Current Period Allocations of Overhead Expense, Reimbursement Of Administration Expense Sterling Place Holdings LLC Sterling Place Holdings LLC [Member] Sterling Place Holdings LLC Subordinated Structured Notes Debt Securities, Subordinate Structured Notes [Member] Debt Securities, Subordinate Structured Notes Average cost per share, gross (usd per share) Shares Acquired, Average Cost Per Share, Gross Shares Acquired, Average Cost Per Share, Gross Derivative Instrument [Axis] Derivative Instrument [Axis] Non-controlled/affiliated Investment, Affiliated Issuer, Noncontrolled [Member] Subsidiary of Limited Liability Company or Limited Partnership [Line Items] Subsidiary of Limited Liability Company or Limited Partnership [Line Items] Consolidated Entities [Axis] Consolidated Entities [Axis] Lucky US BuyerCo LLC Lucky US BuyerCo LLC [Member] Lucky US BuyerCo LLC Average cost per share, gross (usd per share) Shares Acquired, Average Cost Per Share Per Annual Redemption Period Per Annual Redemption Period [Member] Per Annual Redemption Period Series A Series A 5.35% Series A Preferred Stock [Member] 5.35% Series A Preferred Stock Second Exchange Second Exchange [Member] Second Exchange Entity Common Stock, Shares Outstanding Tax reclassification of net assets (Note 12) Investment Company, Tax Reclassification of Net Assets Investment Company, Tax Reclassification of Net Assets Effective yield interest income recognized Investment Owned, Effective Yield Interest Income Recognized Investment Owned, Effective Yield Interest Income Recognized Registration expenses Investment Company, Registration Expense Managerial assistance Managerial Assistance Fee Income Refuel Agency, Inc. Refuel Agency, Inc. [Member] Refuel Agency, Inc. TPS, LLC TPS, LLC [Member] TPS, LLC Related Party Agreements and Transactions Related Party Transactions Disclosure [Text Block] Ownership interest disposed percent Limited Liability Company or Limited Partnership, Members or Limited Partners, Ownership Interest Disposed Limited Liability Company or Limited Partnership, Members or Limited Partners, Ownership Interest Disposed Consolidated Entities [Domain] Consolidated Entities [Domain] Ratio of operating expenses to average net assets applicable to common shares Investment Company Expense Ratio Of Operating Expenses To Average Net Assets Investment Company Expense Ratio Of Operating Expenses To Average Net Assets Freedom Marine Solutions, LLC Freedom Marine Solutions, LLC [Member] Freedom Marine Solutions, LLC Octagon Investment Partners XV, Ltd. Octagon Investment Partners XV, Ltd. [Member] Octagon Investment Partners XV, Ltd. First Tower, LLC First Tower, LLC [Member] First Tower, LLC Investment Company, Nonconsolidated Subsidiary [Axis] Investment Company, Nonconsolidated Subsidiary [Axis] Vesper Campus Quarters, LLC Vesper Campus Quarters, LLC [Member] Vesper Campus Quarters, LLC Common stock, par value (usd per share) Common Stock, Par or Stated Value Per Share Debt Instrument, Redemption, Period [Axis] Debt Instrument, Redemption, Period [Axis] Commercial Services & Supplies Commercial Services & Supplies Sector [Member] Commercial Services & Supplies Sector Accretion of premiums, net Accretion (Amortization) of Discounts and Premiums, Investments Kickapoo Ranch Pet Resort Kickapoo Ranch Pet Resort [Member] Kickapoo Ranch Pet Resort Outstanding Aggregate Erroneous Compensation Amount Outstanding Aggregate Erroneous Compensation Amount Number of reportable segments Number of Reportable Segments Credit Facility Credit Facility [Member] Credit Facility August 15, 2029 – December 15, 2034 Debt Instrument Redemption Period Nineteen [Member] Debt Instrument Redemption Period Nineteen NMMB, Inc. NMMB, Inc. [Member] NMMB, Inc. 6.50% Preferred Stock DRIP 6.50% Preferred Stock DRIP [Member] 6.50% Preferred Stock DRIP Concentration Risk [Table] Concentration Risk [Table] STG Distribution, LLC STG Distribution, LLC [Member] STG Distribution, LLC Net realized gains (losses) from derivative instruments and foreign currency transactions Realized Gain (Loss), Foreign Currency Transaction And Derivatives, after Tax Realized Gain (Loss), Foreign Currency Transaction And Derivatives, after Tax Entity Address, City or Town iQor Holdings, Inc. iQor Holdings, Inc. [Member] iQor Holdings, Inc. Recovery rate Measurement Input, Recovery rate [Member] Measurement Input, Recovery rate Statement of Financial Position [Abstract] Title of Individual [Domain] Title and Position [Domain] O 2027 Q2 Dividends O 2027 Q2 Dividends [Member] O 2027 Q2 Dividends Debt Securities, Second Lien 4 Debt Securities, Second Lien 4 [Member] Debt Securities, Second Lien 4 5.50% Preferred Stock DRIP 5.50% Preferred Stock DRIP [Member] 5.50% Preferred Stock DRIP Second Lien Revolving Line of Credit Debt Securities, Second Lien Revolving Line of Credit [Member] Debt Securities, Second Lien Revolving Line of Credit Peer Group Total Shareholder Return Amount Peer Group Total Shareholder Return Amount Capital Markets Capital Markets Sector [Member] Capital Markets Sector TCSPV Holdings IV, LLC TCSPV Holdings IV, LLC [Member] TCSPV Holdings IV, LLC Taxable income before deductions for distributions Investment Company, Tax Basis, Taxable Income (Loss), before Deduction for Distribution Level 2 Fair Value, Inputs, Level 2 [Member] Total Shareholder Return Vs Peer Group Total Shareholder Return Vs Peer Group [Text Block] Net investment income (in dollars per share) Investment Company, Investment Income (Loss), Per Share, Basic Non-Rule 10b5-1 Arrangement Terminated Non-Rule 10b5-1 Arrangement Terminated [Flag] Liquidation value Temporary Equity, Liquidation Value Temporary Equity, Liquidation Value Series M2 Series M2 Preferred Stock [Member] Series M2 Preferred Stock Investment interest rate Investment Interest Rate Floor Investment, Interest Rate, Floor NPRC Parkton Holdings LLC NPRC Parkton Holdings LLC [Member] NPRC Parkton Holdings LLC Dividends [Domain] Dividends [Domain] Total dividend income Dividend Income Dividend Income, Operating Name of Property [Axis] Name of Property [Axis] Abacus Dermatology Management, LLC Abacus Dermatology Management, LLC [Member] Abacus Dermatology Management, LLC Armed Forces Communications, Inc. Armed Forces Communications, Inc. [Member] Armed Forces Communications, Inc. Subsequent Event Type [Axis] Subsequent Event Type [Axis] Gross Reductions (Cost) Investments in and Advances to Affiliates, at Fair Value, Gross Reductions (Costs) Investments in and Advances to Affiliates, at Fair Value, Gross Reductions (Costs) Concentration Risk Type [Axis] Concentration Risk Type [Axis] Schedule of Long-Term Debt Instruments [Table] Schedule of Long-Term Debt Instruments [Table] Reclassification, Adjustment Revision of Prior Period, Reclassification, Adjustment [Member] Transportation Infrastructure Transportation Infrastructure Sector [Member] Transportation Infrastructure Sector Distributors Distributors Sector [Member] Distributors Sector Use of Estimates Use of Estimates, Policy [Policy Text Block] Related Party [Axis] Related and Nonrelated Parties [Axis] Total other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Debt Securities, First Lien 1 Debt Securities, First Lien1 [Member] Debt Securities, First Lien1 Net Assets Net Assets [Member] Net Assets Maturity Date Range Two Debt Instrument, Redemption, Period Two [Member] Victor Technology, LLC Victor Technology, LLC [Member] Victor Technology, LLC MITY Holdings of Delaware Inc. MITY Holdings of Delaware Inc. [Member] MITY Holdings of Delaware Inc. Preferred Equity 1 Preferred Stock1 [Member] Preferred Stock1 5.00% 2019 Notes 5.00 2019 Notes [Member] 5.00 2019 Notes Document Period End Date Enterprise market cash flow approach and option pricing model Enterprise Market Cash Flow Approach And Option Pricing Model [Member] Enterprise Market Cash Flow Approach And Option Pricing Model Liquidation Trust Liquidation Trust [Member] Liquidation Trust Subsidiaries Subsidiaries [Member] Dividends payable (usd per share) Dividends Payable, Amount Per Share Derivative liabilities: Derivative Liability, Subject to Master Netting Arrangement, after Offset and Deduction [Abstract] Preferred stock, shares outstanding (in shares) Preferred Stock, Shares Outstanding Face amount Debt Instrument, Face Amount Net Assets Applicable to Common Shares Net Assets October 15, 2026 – September 15, 2031 Debt Instrument Redemption Period Fifteen [Member] Debt Instrument Redemption Period Fifteen 5.50% Series AA1 Preferred Stock 5.50% Series AA1 Preferred Stock [Member] 5.50% Series AA1 Preferred Stock Effective Interest Rate Debt Instrument, Interest Rate, Effective Percentage Conversion of preferred stock to common stock (in shares) Conversion of preferred stock to common stock (in shares) Temporary Equity, Shares, Conversion of Convertible Securities Temporary Equity, Shares, Conversion of Convertible Securities RME Group Holding Company RME Group Holding Company [Member] RME Group Holding Company Abbie Lakes OH Partners, LLC Abbie Lakes OH Partners, LLC [Member] Abbie Lakes OH Partners, LLC Accumulated other comprehensive income (loss) Accumulated Other Comprehensive Income (Loss), Net of Tax Entity Shell Company Consolidation Items [Domain] Consolidation Items [Domain] TP Cheyenne, LLC TP Cheyenne, LLC [Member] TP Cheyenne, LLC Energy Equipment & Services Energy Equipment & Services Sector [Member] Energy Equipment & Services Sector The RK Logistics Group, Inc. The RK Logistics Group, Inc. [Member] The RK Logistics Group, Inc. Schedule of Composition of Investment Portfolio Investment Holdings, Schedule of Investments [Table Text Block] Net Increase (Decrease) in Net Assets per Common Share Earnings Per Share [Text Block] Series AA2 6.50% Series AA2 Preferred Stock [Member] 6.50% Series AA2 Preferred Stock Basic and diluted earnings (loss) per common share (Note 11) Earnings Per Share [Abstract] O 2027 M7 Dividends O 2027 M7 Dividends [Member] O 2027 M7 Dividends Lakeview Trail OH Partners, LLC Lakeview Trail OH Partners, LLC [Member] Lakeview Trail OH Partners, LLC Document Fiscal Period Focus USES Corp. USES Corp. [Member] USES Corp. Peer Group Issuers, Footnote Peer Group Issuers, Footnote [Text Block] Capital Transactions Investment Company, Capital Share Transaction, Increase (Decrease) [Abstract] Total Liabilities  Liabilities Trading Symbol Discount Rate Measurement Input, Discount Rate [Member] USG Intermediate, LLC USG Intermediate, LLC [Member] USG Intermediate, LLC Company Selected Measure Name Company Selected Measure Name Sale of Stock [Domain] Sale of Stock [Domain] STG Topco, LLC STG Topco, LLC [Member] STG Topco, LLC Repurchase of preferred stock (in shares) Temporary Equity, Shares, Repurchase of Preferred Stock Temporary Equity, Shares, Repurchase of Preferred Stock Income Tax Disclosure [Abstract] Concentration Risk [Line Items] Concentration Risk [Line Items] Fair value adjustment Fair Value Adjustment Fair Value Adjustment Kengary Way OH Partners, LLC Kengary Way OH Partners, LLC [Member] Kengary Way OH Partners, LLC Trading Companies & Distributors Trading Companies & Distributors Sector [Member] Trading Companies & Distributors Sector Debt Repayment Condition [Axis] Debt Repayment Condition [Axis] Debt Repayment Condition Credit Facility [Domain] Credit Facility [Domain] Redemption limit, percent Temporary Equity, Redemption Limit, Percent Temporary Equity, Redemption Limit, Percent Operating Activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract] 23275 Riverside Drive Owner, LLC 23275 Riverside Drive Owner, LLC [Member] 23275 Riverside Drive Owner, LLC Other temporary book-to-tax differences Investment Company, Tax Basis, Other, Increase (Decrease) Equity Valuation Assumption Difference, Footnote Equity Valuation Assumption Difference, Footnote [Text Block] Non-accrual loans Debt Securities, Non-Accrual Status [Member] Debt Securities, Non-Accrual Status Line of Credit Facility [Table] Line of Credit Facility [Table] Transfers out of Level 3 Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3 Received terminated amount Proceeds from Derivative Instrument, Financing Activities Other Income Disclosure [Abstract] Other Income Disclosure Dividends payable Dividends Payable Verify Diagnostics LLC Verify Diagnostics LLC [Member] Verify Diagnostics LLC Halcyon Loan Advisors Funding 2015-3 Ltd. Halcyon Loan Advisors Funding 2015-3 Ltd. [Member] Halcyon Loan Advisors Funding 2015-3 Ltd. Schedule of Changes in Fair Value of Level 3 Investments Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Financing Costs Deferred Charges, Policy [Policy Text Block] Investment, basis spread, variable rate, TLA and TLD Investment, Basis Spread, Variable Rate, TLA and TLD Investment, Basis Spread, Variable Rate, TLA and TLD Other general and administrative expenses Other General and Administrative Expense Cash, Cash Equivalents and Restricted Cash Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block] Jackson Crosswinds LLC Jackson Crosswinds LLC [Member] Jackson Crosswinds LLC Investment Company, Financial Highlights [Roll Forward] Investment Company, Financial Highlights [Roll Forward] Repurchase of Public Notes (Note 5) Repayments Of Public Debt Repayments Of Public Debt June 15, 2033 – July 15, 2033 Debt Instrument Redemption Period Twenty [Member] Debt Instrument Redemption Period Twenty Temporary equity, early redemption fee, period after issuance Temporary Equity, Early Redemption Fee, Period After Issuance Temporary Equity, Early Redemption Fee, Period After Issuance Award Timing Predetermined Award Timing Predetermined [Flag] Net Realized and Net Change in Unrealized Gains (Losses) from Investments Net Realized and Net Change in Unrealized Gains (Losses) from Investments [Abstract] Net Realized and Net Change in Unrealized Gains (Losses) from Investments BCPE North Start US Holdco 2, Inc. BCPE North Start US Holdco 2, Inc. [Member] BCPE North Start US Holdco 2, Inc. Adjustment To PEO Compensation, Footnote Adjustment To PEO Compensation, Footnote [Text Block] Level 1 Fair Value, Inputs, Level 1 [Member] 5.35% Preferred Stock 5.35% Series A Fixed Rate Cumulative Perpetual Preferred Stock [Member] 5.35% Series A Fixed Rate Cumulative Perpetual Preferred Stock Schedule of Industries Comprising Greater than 10% of Portfolio Fair Value Schedules of Concentration of Risk, by Risk Factor [Table Text Block] Valley Electric Co. of Mt. Vernon, Inc. Valley Electric Co. of Mt. Vernon, Inc. [Member] Valley Electric Co. of Mt. Vernon, Inc. Stryker Energy, LLC Stryker Energy, LLC [Member] Stryker Energy, LLC Valora at Homewood Holdings LLC Valora at Homewood Holdings LLC [Member] Valora at Homewood Holdings LLC Administration Agreement Administration Agreement [Member] Administration Agreement SPCP Hampton LLC SPCP Hampton LLC [Member] SPCP Hampton LLC Net realized (losses) gains on investments Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings, Realized Gains (Loss) Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings, Realized Gains (Loss) Nationwide Loan Company LLC Nationwide Acceptance Holdings LLC [Member] Nationwide Acceptance Holdings LLC Affiliate investments Investment, Affiliated Issuer [Member] O 2026 M1 Dividends O 2026 M1 Dividends [Member] O 2026 M1 Dividends Liquidation Preference Outstanding Temporary Equity, Liquidation Preference, Value of Shares Outstanding Temporary Equity, Liquidation Preference, Value of Shares Outstanding Total Net Operating Expenses Investment Company, Expense, after Reduction of Fee Waiver and Reimbursement Repayments and sales of portfolio investments Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales And Settlements Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales And Settlements Preferred stock, par value (usd per share) Preferred Stock, Par or Stated Value Per Share Fair Value Long-Term Debt, Fair Value Scenario [Domain] Scenario [Domain] Administration Other Affiliates [Member] Wolf Energy Services Company, LLC Wolf Energy Services Company, LLC [Member] Wolf Energy Services Company, LLC Concentration Risk Type [Domain] Concentration Risk Type [Domain] 2030 Notes 2030 Notes [Member] 2030 Notes Reclassified into earnings Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net 2020 Notes 2020 Notes [Member] 2020 Notes Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Technology Hardware, Storage & Peripherals Technology Hardware, Storage & Peripherals Sector [Member] Technology Hardware, Storage & Peripherals Sector Revolving Credit Facility (Notes 4 and 8) Credit facility outstanding balance Long-Term Line of Credit Payments of dividends, common stock Payments of Ordinary Dividends, Common Stock Issuable Upon Conversion Issuable Upon Conversion [Member] Issuable Upon Conversion Expiration Date Trading Arrangement Expiration Date Debt Securities, Second Lien 3 Debt Securities, Second Lien 3 [Member] Debt Securities, Second Lien 3 Net Increase (Decrease) in Cash, Cash Equivalents and Restricted Cash Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Excluding Exchange Rate Effect, Including Discontinued Operation 2031 Long-Term Debt, Maturity, Year Four Hedging Relationship [Axis] Hedging Relationship [Axis] NPRC Wolfchase LLC NPRC Wolfchase LLC [Member] NPRC Wolfchase LLC Voya CLO 2012-4, Ltd. Voya CLO 2012-4, Ltd. [Member] Voya CLO 2012-4, Ltd. Gross Amounts of Financial Instruments Not Offset in Consolidated Statements of Assets and Liabilities Derivative Asset, Subject to Master Netting Arrangement, Deduction of Financial Instrument Not Offset Wellful Inc. Wellful Inc. [Member] Wellful Inc. Total increase (decrease) during period (in shares) Common Stock, Shares, Outstanding, Increase (Decrease) Common Stock, Shares, Outstanding, Increase (Decrease) Net Amount Derivative Asset, Subject to Master Netting Arrangement, after Offset and Deduction Asset recovery analysis Valuation Technique, Asset Recovery Analysis [Member] Valuation Technique, Asset Recovery Analysis Subordinated Structured Notes Subordinated Debt [Member] Nonrelated Party Nonrelated Party [Member] 5.50% Preferred Stock 5.50% Preferred Stock [Member] 5.50% Preferred Stock Affiliated Entity Affiliated Entity [Member] Diversified Telecommunication Services Diversified Telecommunication Services Sector [Member] Diversified Telecommunication Services Sector Notes Unsecured Debt Aggregate Pension Adjustments Service Cost Aggregate Pension Adjustments Service Cost [Member] Reclassification from accumulated other comprehensive income (loss) into interest expense Gain (Loss) on Discontinuation of Cash Flow Hedge Due to Forecasted Transaction Probable of Not Occurring, Net Derivative [Table] Derivative [Table] Net Investment Income Net investment income Operating income Investment Income, Operating, after Expense and Tax Royalty/Net Interest Royalty Net Interest Royalty Net Interest Survivor’s Option Survivor’s Option [Member] Survivor’s Option 9220 Old Lantern Way, LLC 9220 Old Lantern Way, LLC [Member] 9220 Old Lantern Way, LLC 7915 Baymeadows Circle Owner, LLC 7915 Baymeadows Circle Owner, LLC [Member] 7915 Baymeadows Circle Owner, LLC Credit Central of Tennessee, LLC Credit Central of Tennessee, LLC [Member] Credit Central of Tennessee, LLC Related Party Transaction [Axis] Related Party Transaction [Axis] Discovery Point Retreat, LLC. Discovery Point Retreat, LLC. [Member] Discovery Point Retreat, LLC. Nixon, Inc. Nixon, Inc. [Member] Nixon, Inc. Benchmark percept of share price Benchmark Percept Of Share Price Benchmark Percept Of Share Price Temporary Equity [Line Items] Temporary Equity [Line Items] Revolving Credit Facility Fair Value and Maturity of Debt Outstanding Debt Disclosure [Text Block] Senior Living Senior Living [Member] Senior Living Scenario [Axis] Scenario [Axis] Investment Advisory And Management Agreement Incentive Rate Quarterly Hurdle Rate Investment Advisory And Management Agreement Incentive Rate Quarterly Hurdle Rate [Member] Investment Advisory And Management Agreement Incentive Rate Quarterly Hurdle Rate Convertible Preferred Stock Convertible Preferred Stock [Member] 2024 Notes 2024 Notes [Member] 2024 Notes Deferred financing costs on Revolving Credit Facility (Note 4) Debt financing costs Debt Issuance Costs, Net After 5 Years Long-Term Debt, Maturity, After Year Four Long-Term Debt, Maturity, After Year Four Open Forward Foreign Currency Contract, Identifier [Axis] Open Forward Foreign Currency Contract, Identifier [Axis] PEO Actually Paid Compensation Amount PEO Actually Paid Compensation Amount Issuance of preferred stock (in shares) Shares Issued (in shares) Temporary Equity, Stock Issued During Period, Shares, New Issues Temporary Equity, Stock Issued During Period, Shares, New Issues Vesper Corpus Christi, LLC Vesper Corpus Christi, LLC, Corpus Christi, TX [Member] Vesper Corpus Christi, LLC, Corpus Christi, TX Number of accredited investors Number of Accredited Investors Number of Accredited Investors Stated rate Interest Rate Range Debt Instrument, Interest Rate, Stated Percentage Net Assets Applicable to Common Shares Beginning of period, Net Assets End of period, Net Assets Net assets at end of year Equity, Attributable to Parent Adjustment for dividends on Convertible Preferred Stock Convertible Preferred Dividends, Net of Tax, Adjustment Convertible Preferred Dividends, Net of Tax, Adjustment Investment Company, Nonconsolidated Subsidiary [Table] Investment Company, Nonconsolidated Subsidiary [Table] Taco Bell, MO Taco Bell, Mo [Member] Taco Bell, Mo Common Equity/Interests/Warrants 3 Common Stock, Interests Or Warrants3 [Member] Common Stock, Interests Or Warrants3 Health Care Equipment & Supplies Health Care Equipment & Supplies Sector [Member] Health Care Equipment & Supplies Sector Incentive fee Incentive Fee Payable Real Estate [Domain] Real Estate [Domain] Health Care Providers & Services Health Care Providers & Services Sector [Member] Health Care Providers & Services Sector NPRC Lancaster LLC NPRC Lancaster LLC [Member] NPRC Lancaster LLC Assets Assets [Abstract] Series A Preferred Stock ATM Program Series A Preferred Stock ATM Program [Member] Series A Preferred Stock ATM Program EBITDA multiple Measurement Input, EBITDA Multiple [Member] Due from broker Receivable from Broker-Dealer and Clearing Organization 8025 Baymeadows Circle Owner, LLC 8025 Baymeadows Circle Owner, LLC [Member] 8025 Baymeadows Circle Owner, LLC Minimum annualized dividend rate Temporary Equity, Minimum Annualized Dividend Rate Temporary Equity, Minimum Annualized Dividend Rate DRI Holding Inc. DRI Holding Inc. [Member] DRI Holding Inc. Financing Receivable Name [Domain] Financing Receivable Name [Domain] Financing Receivable Name [Domain] Audit, compliance and tax related fees Professional Fees Insider Trading Policies and Procedures [Line Items] Investment, Issuer Affiliation [Domain] Investment, Issuer Affiliation [Domain] O 2027 M5 Dividends O 2027 M5 Dividends [Member] O 2027 M5 Dividends Interest rate Loans To Portfolio Companies, Interest Rate Loans To Portfolio Companies, Interest Rate Number of operating segments Number of Operating Segments Antidilutive securities excluded from computation (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount 2nd Lien Term Loan Debt Securities, 2nd Lien Term Loan [Member] Debt Securities, 2nd Lien Term Loan Redemption price rate Temporary Equity, Redemption Price, Rate Temporary Equity, Redemption Price, Rate Entity Central Index Key Structured Finance Structured Finance Sector [Member] Structured Finance Sector Collections Acquisition Company, Inc. Collections Acquisition Company, Inc. [Member] Collections Acquisition Company, Inc. Equity [Abstract] Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year [Member] Series M3 6.50% Series M3 Preferred Stock [Member] 6.50% Series M3 Preferred Stock First Lien Term Loan B First Lien Term Loan B [Member] First Lien Term Loan B 2027 Long-Term Debt, Maturity, Remainder of Fiscal Year Distributions to Shareholders (Note 12) Investment Company, Distribution to Shareholders [Abstract] Common Equity/Interests/Warrants 2 Common Stock, Interests Or Warrants2 [Member] Common Stock, Interests Or Warrants2 Ownership [Axis] Ownership [Axis] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Financial Services Financial Service Sector [Member] Financial Service Sector Schedule of Investments [Line Items] Schedule of Investments [Line Items] Inception to Date Preferred Shares Sold via Offering Temporary Equity, Shares Issued Inception to Date Temporary Equity, Shares Issued Inception to Date Amount Distributed Dividends, Preferred Stock, Cash Dividend Income Revenue Recognition, Dividends [Policy Text Block] Investment, Name [Axis] Investment, Name [Axis] Net realized and change in unrealized gains (losses) (in dollars per share) Investment Company, Gain (Loss) on Investment, Per Share Designated as Hedging Instrument Designated as Hedging Instrument [Member] Dividend rate Preferred Stock, Dividend Rate, Percentage Professional Services Professional Services Sector [Member] Professional Services Sector Machinery Machinery Sector [Member] Machinery Sector Net change in unrealized gains (losses) Net change in unrealized losses (gains) on investments Net unrealized gains (losses) Debt and Equity Securities, Unrealized Gain (Loss) Basis spread Debt Instrument, Basis Spread on Variable Rate Schedule of Dividends Payable Schedule of Dividends Payable [Table Text Block] Variable Rate [Domain] Variable Rate [Domain] Maturity Date Range One Debt Instrument, Redemption, Period One [Member] Unfunded commitments Debt Securities, Unfunded Commitments [Member] Debt Securities, Unfunded Commitments Accumulated Other Comprehensive Income AOCI Attributable to Parent [Member] Distributions of net investment income (in dollars per share) Investment Company, Distribution of Net Investment Income to Shareholders, Per Share Investment Company, Distribution of Net Investment Income to Shareholders, Per Share Common Equity/Interests/Warrants 1 Common Stock, Interests Or Warrants1 [Member] Common Stock, Interests Or Warrants1 Imperative Worldwide, LLC Imperative Worldwide, LLC [Member] Imperative Worldwide, LLC All Individuals All Individuals [Member] Investment, Issuer Name [Domain] Investment, Issuer Name [Domain] Number of equity positions transferred Number Of Equity Positions Transferred Number Of Equity Positions Transferred IT Services IT Services Sector [Member] IT Services Sector Dividends paid and distributions to common and preferred stockholders Payments of Dividends Pacific World Corporation Pacific World Corporation [Member] Pacific World Corporation Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Net realized gains (losses) Net realized losses on investments Realized (Loss) Gain Realized Gain Debt and Equity Securities, Realized Gain (Loss) 6.50% Preferred Stock 6.50% Preferred Stock [Member] 6.50% Preferred Stock Orlando 442 Owner, LLC (West Vue Apartments) Orlando 442 Owner, LLC (West Vue Apartments) [Member] Orlando 442 Owner, LLC (West Vue Apartments) PIK Rate - Paid as cash Investment, Interest Rate, Paid as Cash Investment, Interest Rate, Paid as Cash NPRC and Subsidiaries NPRC and Subsidiaries [Member] NPRC and Subsidiaries Consumer Finance Consumer Finance Sector [Member] Consumer Finance Sector Statement [Line Items] Statement [Line Items] Total Assets  Assets Enterprise market & discounted cash flow approach and option pricing model Valuation, Enterprise Market & Discounted Cash Flow Approach And Option Pricing Model [Member] Valuation, Enterprise Market & Discounted Cash Flow Approach And Option Pricing Model Prospect Capital Funding LLC Prospect Capital Funding LLC [Member] Prospect Capital Funding LLC Interest and credit facility expenses Interest Expense, Operating Wolf Energy, LLC Wolf Energy, LLC [Member] Wolf Energy, LLC Capital shares reserved for future issuance (in shares) Common Stock, Capital Shares Reserved for Future Issuance Convertible Notes Convertible Debt [Member] Industry Sector [Axis] Industry Sector [Axis] Reportable Legal Entities Reportable Legal Entities [Member] Capital Transactions Temporary Equity, Capital Transactions [Abstract] Temporary Equity, Capital Transactions Discovery Point Retreat, LLC Discovery Point Retreat, LLC 1 [Member] Discovery Point Retreat, LLC 1 Interest expense Interest Expense, Nonoperating Galaxy XXVIII CLO, Ltd. Galaxy XXVIII CLO, Ltd. [Member] Galaxy XXVIII CLO, Ltd. Excise tax expense Investment Company, Excise Tax Expense Administration agreement, termination period without penalties Administration Agreement, Termination Period Without Penalties Administration Agreement, Termination Period Without Penalties PEO PEO [Member] Adjustment for Incentive Fee on Convertible Instruments Dilutive Securities, Effect on Basic Earnings Per Share, Adjustment for Incentive Fee on Convertible Instruments Dilutive Securities, Effect on Basic Earnings Per Share, Adjustment for Incentive Fee on Convertible Instruments Investment Advisory And Management Agreement Incentive Rate Annual Catch Up Threshold Member Investment Advisory And Management Agreement Incentive Rate Annual Catch Up Threshold Member [Member] Investment Advisory And Management Agreement Incentive Rate Annual Catch Up Threshold Member 2029 Long-Term Debt, Maturity, Year Two Diversified Consumer Services Diversified Consumer Services Sector [Member] Diversified Consumer Services Sector (Increase) decrease in prepaid expenses Increase (Decrease) in Prepaid Expense Rosa Mexicano Rosa Mexicano [Member] Rosa Mexicano Interest at Fixed Rates Debt Securities, Fixed Interest Rate [Member] Debt Securities, Fixed Interest Rate Forgone Recovery due to Violation of Home Country Law, Amount Forgone Recovery due to Violation of Home Country Law, Amount Redemption of Preferred Stock Temporary Equity, Shares, Redemption of Preferred Stock, Value Temporary Equity, Shares, Redemption of Preferred Stock, Value Gross Amounts of Financial Instruments Not Offset in Consolidated Statements of Assets and Liabilities Derivative Liability, Subject to Master Netting Arrangement, Deduction of Financial Instrument Not Offset Broda Enterprises ULC Broda Enterprises ULC [Member] Broda Enterprises ULC Distributions in excess of earnings Retained Earnings [Member] Tangible book value multiple Measurement Input, Tangible Book Value Multiple [Member] Measurement Input, Tangible Book Value Multiple Revolving Credit Facility Revolving Credit Facility [Member] Investment Valuation Fair Value Measurement, Policy [Policy Text Block] Net increase (decrease) from operations (in dollars per share) Investment Company, Investment Income (Loss) from Operations, Per Share Common stock, shares outstanding (in shares) Beginning balance, Common stock, shares outstanding (in shares) Ending balance, Common stock, shares outstanding (in shares) Shares of common stock outstanding at end of year (in shares) Common Stock, Shares, Outstanding Award Timing Disclosures [Line Items] Diluted (in dollars per share) Earnings (loss) per share - diluted (in dollars per share) Earnings Per Share, Diluted Gain reclassified from AOCI into income as a result of forecasted transactions no longer probable of occurring Other Comprehensive Income (Loss), Cash Flow Hedge, Reclassification for Discontinuance, After Tax Other Comprehensive Income (Loss), Cash Flow Hedge, Reclassification for Discontinuance, After Tax Prospect Administration LLC Prospect Administration LLC [Member] Prospect Administration LLC Total Interest Income Capitalized as PIK Interest Income Capitalized as PIK Interest Costs Capitalized Interest Costs Capitalized Income incentive fee (Note 13) Income incentive fee Incentive Fee Expense Belnick, LLC (d/b/a The Ubique Group) Belnick, LLC Belnick, LLC [Member] Belnick, LLC Total interest income (excluding PIK interest income) Interest Income, Operating, Paid in Cash R-V Holdings of Delaware, LLC R-V Holdings of Delaware, LLC [Member] R-V Holdings of Delaware, LLC 2018 Notes 2018 Notes [Member] 2018 Notes Ownership [Domain] Ownership [Domain] Borrowings under Revolving Credit Facility (Note 4) Proceeds from Long-Term Lines of Credit 2028 Notes 2028 Notes [Member] 2028 Notes InspereX LLC Dealer Manager Agreement InspereX LLC Dealer Manager Agreement [Member] InspereX LLC Dealer Manager Agreement Term Loan A Term Loan A [Member] Term Loan A Schedule of Offsetting Assets Offsetting Assets [Table Text Block] Weighted average common shares from assumed conversion of Convertible Preferred Stock (in shares) Incremental Common Shares Attributable to Dilutive Effect of Conversion of Preferred Stock Remaining borrowing capacity Line of Credit Facility, Remaining Borrowing Capacity VE Company, Inc. VE Company, Inc. [Member] VE Company, Inc. Ownership interest Limited Liability Company or Limited Partnership, Members or Limited Partners, Ownership Interest Total return based on market value Investment Company, Total Return, Market Value K&N HoldCo, LLC K&N HoldCo, LLC [Member] K&N HoldCo, LLC Preferred Capital Securities, LLC Dealer Manager Agreement Preferred Capital Securities, LLC Dealer Manager Agreement [Member] Preferred Capital Securities, LLC Dealer Manager Agreement Accretion of discounts and premiums, net Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Accretion (Amortization) Of Discounts And Premiums, Net Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Accretion (Amortization) Of Discounts And Premiums, Net ShiftKey, LLC ShiftKey, LLC [Member] ShiftKey, LLC Equity Awards Adjustments, Footnote Equity Awards Adjustments, Footnote [Text Block] O 2026 Q1 Dividends O 2026 Q1 Dividends [Member] O 2026 Q1 Dividends January 15, 2028 – August 15, 2033 Debt Instrument Redemption Period Seventeen [Member] Debt Instrument Redemption Period Seventeen 150 Steeplechase Way Owner, LLC 150 Steeplechase Way Owner, LLC [Member] 150 Steeplechase Way Owner, LLC SSN SSN [Member] SSN Over-Allotment Option Over-Allotment Option [Member] Increase (decrease) in interest payable Increase (Decrease) in Interest Payable, Net Net gain (loss) on redemptions of Preferred Stock Net (Loss) Gain On Redemptions Of Preferred Stock Net (Loss) Gain On Redemptions Of Preferred Stock Schedule of Summarized Financial Information for NPRC Investment Company, Nonconsolidated Subsidiary, Summarized Financial Information [Table Text Block] Gains (losses) on excluded components relating to forward points Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), before Adjustments, after Tax Receivables for: Receivable [Abstract] Receivable Investment, Issuer Name [Axis] Investment, Issuer Name [Axis] Halcyon Loan Advisors Funding 2014-2 Ltd. Halcyon Loan Advisors Funding 2014-2 Ltd. [Member] Halcyon Loan Advisors Funding 2014-2 Ltd. Health Care Technology Health Care Technology Sector [Member] Health Care Technology Sector MITY-Lite, Inc. MITY-Lite, Inc. [Member] MITY-Lite, Inc. Silver Hill Mineral Lease Silver Hill Mineral Lease [Member] Silver Hill Mineral Lease Value of shares issued through reinvestment of dividends Stock Issued Schedule of Maturities of Long-Term Debt Schedule of Maturities of Long-Term Debt [Table Text Block] Druid City Infusion, LLC Druid City Infusion, LLC [Member] Druid City Infusion, LLC Calculated interest basis, days Calculated Interest Basis, Days Calculated Interest Basis, Days Title of Individual [Axis] Title and Position [Axis] Sale of Stock [Axis] Sale of Stock [Axis] Multi-Family Multifamily [Member] Net gains from accumulated other comprehensive income (loss) Gain (loss) recognized in Income Derivative, Gain (Loss) on Derivative, Net Schedule of Dividends Declared and Paid Dividends Declared [Table Text Block] Related Party Transaction [Domain] Related Party Transaction [Domain] Palmetto Creek Holdings LLC Palmetto Creek Holdings LLC [Member] Palmetto Creek Holdings LLC Redemption of Preferred Stock (in shares) Temporary Equity, Shares, Redemption of Preferred Stock, Shares Temporary Equity, Shares, Redemption of Preferred Stock, Shares Number of assets transferred out of Level 3 to Level 2 Number of Assets Transferred Out Of Level 3 To Level 2 Number of Assets Transferred Out Of Level 3 To Level 2 Energy Solutions Holdings Inc. Energy Solutions Holdings Inc. [Member] Energy Solutions Holdings Inc. Rule 10b5-1 Arrangement Adopted Rule 10b5-1 Arrangement Adopted [Flag] Investments at fair value Investments at fair value Fair value, beginning balance Fair value, ending balance Investment, fair value Investment Owned, Fair Value Equity Equity Equity Securities [Member] Allocation of overhead from Prospect Administration (Note 13) Allocation of overhead Administrative Fees Expense Cent CLO 21 Limited Cent CLO 21 Limited [Member] Cent CLO 21 Limited Common stock, shares issued (in shares) Common Stock, Shares, Issued Effect of other comprehensive income (in dollars per share) Investment Company, Effect Of Other Comprehensive Income Investment Company, Effect Of Other Comprehensive Income Fair value, beginning balance Fair value, ending balance Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value Jackson Lakeshore Landing LLC Jackson Lakeshore Landing LLC [Member] Jackson Lakeshore Landing LLC 5.35% Preferred Stock 5.35% Preferred Stock [Member] 5.35% Preferred Stock Forward Contracts Forward Contracts [Member] Wolf Energy Wolf Energy [Member] Wolf Energy Gains (losses) on excluded components relating to forward points Gain (Loss) from Components Excluded from Assessment of Cash Flow Hedge Effectiveness, Net Willows at North End Owner LLC Willows at North End Owner LLC [Member] Willows at North End Owner LLC Class of Stock [Line Items] Class of Stock [Line Items] Series M1 Series M1 5.50% Series M1 Preferred Stock [Member] 5.50% Series M1 Preferred Stock Heatherbridge OH Partners, LLC Heatherbridge OH Partners, LLC [Member] Heatherbridge OH Partners, LLC California CALIFORNIA Yatesville Coal Company, LLC Yatesville Coal Company, LLC [Member] Yatesville Coal Company, LLC CP Holdings of Delaware LLC CP Holdings of Delaware LLC [Member] CP Holdings of Delaware LLC Series A Preferred Stock In July 2021 Series A Preferred Stock In July 2021 [Member] Series A Preferred Stock In July 2021 Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] Amount ($ per share), before pro ration for partial periods Temporary Equity, Dividends Per Share, Declared Temporary Equity, Dividends Per Share, Declared Global Tel*Link Corporation (d/b/a ViaPath Technologies.) Global Tel*Link Corporation (d/b/a ViaPath Technologies.) [Member] Global Tel*Link Corporation (d/b/a ViaPath Technologies.) Termination Date Trading Arrangement Termination Date With Weighted Average Interest Rate With Weighted Average Interest Rate [Member] With Weighted Average Interest Rate Common Equity/Interests/Warrants 6 Common Stock, Interests Or Warrants6 [Member] Common Stock, Interests Or Warrants6 Subsequent Events [Abstract] Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Derivative assets: Derivative Asset, Subject to Master Netting Arrangement, before Offset of Collateral [Abstract] Schedule of Investment Company, Distribution to Shareholders Investment Company, Distribution To Shareholders [Table Text Block] Investment Company, Distribution To Shareholders Compensation Actually Paid vs. Total Shareholder Return Compensation Actually Paid vs. Total Shareholder Return [Text Block] ProHaul Transports, LLC ProHaul Transports, LLC [Member] ProHaul Transports, LLC Upstream Holdco, Inc. Upstream Holdco, Inc. [Member] Upstream Holdco, Inc. Fair Value as of Grant Date Award Grant Date Fair Value Preferred Equity 2 Preferred Stock2 [Member] Preferred Stock2 In Accordance With Survivor’s Option In Accordance With Survivor’s Option [Member] In Accordance With Survivor’s Option Redemption price rate Debt Instrument, Redemption Price, Percentage Spartan Term Loans Spartan Term Loans [Member] Spartan Term Loans Preferred Stock Preferred Stock Policy [Policy Text Block] Preferred Stock Policy Precisely Software Incorporated Precisely Software Incorporated [Member] Precisely Software Incorporated Increase (Decrease) in Temporary Equity [Roll Forward] Increase (Decrease) in Temporary Equity [Roll Forward] Pay vs Performance Disclosure, Table Pay vs Performance [Table Text Block] Stock repurchase program, remaining authorized repurchase amount Share Repurchase Program, Remaining Authorized, Amount Jackson Reflection Pointe LLC Jackson Reflection Pointe LLC [Member] Jackson Reflection Pointe LLC Arrangement Duration Trading Arrangement Duration Temporary equity, liquidation preference (usd per share) Temporary Equity, Liquidation Preference Per Share Consolidation Items [Axis] Consolidation Items [Axis] Entity Address, Postal Zip Code Entity Registrant Name Insider Trading Policies and Procedures Not Adopted Insider Trading Policies and Procedures Not Adopted [Text Block] More than 60% Drawn Credit Facility, Usage, More than 60% Drawn [Member] Credit Facility, Usage, More than 60% Drawn Food & Staples Retailing Food & Staples Retailing Sector [Member] Food & Staples Retailing Sector Forgone Recovery due to Expense of Enforcement, Amount Forgone Recovery due to Expense of Enforcement, Amount Appalachian Energy LLC Appalachian Energy LLC [Member] Appalachian Energy LLC Common Equity/Interests/Warrants 8 Common Stock, Interests Or Warrants8 [Member] Common Stock, Interests Or Warrants8 Total PIK Interest Income Interest Income, Operating, Paid in Kind MITY, Inc. MITY, Inc. [Member] MITY, Inc. 2016 Notes 2016 Notes [Member] 2016 Notes Beginning balance, temporary equity Ending balance, temporary equity Temporary Equity, Carrying Amount, Attributable to Parent Net change in unrealized (gains) losses from derivative instruments and foreign currency transactions Unrealized Gain (Loss), Derivative and Foreign Currency Transaction Price Change, Operating, before Tax All Award Types Award Type [Domain] Administrative agent fees Administrative Agent Administrative Agent Fees Administrative Agent Fees Revenue multiple Measurement Input, Revenue Multiple [Member] Level 3 Fair Value, Inputs, Level 3 [Member] Restructured debt Investment Company, Recapitalization Equity Securities Converted Investment Company, Recapitalization Equity Securities Converted Share price (usd per share) Geographical [Axis] Geographical [Axis] Diversified Financial Services Diversified Financial Services Sector [Member] Diversified Financial Services Sector Increase (decrease) in accrued expenses Increase (Decrease) in Accrued Liabilities 2025 Notes 2025 Notes [Member] 2025 Notes Derivative Instruments Summary of Derivative Instruments [Abstract] Uncommitted funds Investment Company, Financial Support to Investee Contractually Required, Amount Restricted cash Restricted Cash Reimbursement of Legal, Tax, etc Reimbursement of Legal, Tax, etc Investment Company, Professional Fee Income Investment Company, Professional Fee Income Residential Real Estate Investment Trusts (REITs) Residential Real Estate Investment Trusts (REITs) [Member] Residential Real Estate Investment Trusts (REITs) Investment, Issuer Affiliation [Axis] Investment, Issuer Affiliation [Axis] Southport Owner LLC (Southport Crossing) Southport Owner LLC (Southport Crossing) [Member] Southport Owner LLC (Southport Crossing) Legal Entity [Axis] Interest expense Interest cost Interest Expense, Debt Cash, Cash Equivalents and Restricted Cash at beginning of period Cash, Cash Equivalents and Restricted Cash at End of Period Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Gross Amounts of Cash Collateral Received (Pledged) from Counterparty Not Offset in Consolidated Statements of Assets and Liabilities Derivative Liability, Subject to Master Netting Arrangement, Collateral, Right to Reclaim Cash Not Offset Barings CLO 2018-III Barings CLO 2018-III [Member] Barings CLO 2018-III Filing One Filing One [Member] Filing One Investment company, distributable earnings (loss), accumulated capital loss carryforward Investment Company, Distributable Earnings (Loss), Accumulated Capital Loss Carryforward Parkside at Laurel West Owner LLC Parkside at Laurel West Owner LLC [Member] Parkside at Laurel West Owner LLC Non-NEOs Non-NEOs [Member] Equity ownership percentage Equity Method Investment, Ownership Percentage Household Products Household Products Sector [Member] Household Products Sector Net Amounts Presented in the Consolidated Statement of Assets and Liabilities Derivative Liability, Subject to Master Netting Arrangement, before Offset of Collateral Investment, Name [Domain] Investment, Name [Domain] Inception to Date Liquidation Preference Issued via Offering Temporary Equity, Liquidation Preference, Value, Inception to Date Temporary Equity, Liquidation Preference, Value, Inception to Date 2028 Long-Term Debt, Maturity, Year One Long-Term Debt, Type [Domain] Long-Term Debt, Type [Domain] Net realized losses Debt and Equity Securities, Realized Gain (Loss) Net of Gain (Loss) from Debt Extinguishment Debt and Equity Securities, Realized Gain (Loss) Net of Gain (Loss) from Debt Extinguishment Statistical Measurement [Axis] Statistical Measurement [Axis] Base management fee rate Management and Service Fees, Base Rate 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 Derivative Instruments, Gain (Loss) [Table Text Block] Award Type Award Type [Axis] Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] Net unrealized loss Investment, Tax Basis, Unrealized Gain (Loss) Distributions in excess of earnings (Note 12) Retained Earnings (Accumulated Deficit) Retained Earnings (Accumulated Deficit) Redemptions of Preferred Stock Payments for Redemption of Preferred Stock Payments for Redemption of Preferred Stock Trading days Debt Instrument, Convertible, Threshold Trading Days Valley Electric Holdings II, Inc. Valley Electric Holdings II, Inc. [Member] Valley Electric Holdings II, Inc. Awards Close in Time to MNPI Disclosures Awards Close in Time to MNPI Disclosures [Table] Net proceeds after deducting estimated offering expenses Proceeds from Issuance of Secured Debt Common Stock Common Stock [Member] Interactive Media & Services Interactive Media & Services Sector [Member] Interactive Media & Services Sector Net realized (gains) losses on investments Investment, Tax Basis Reconciliation, Net Realized Gains (Losses) On Investments, Increase (Decrease) In Taxable Income Investment, Tax Basis Reconciliation, Net Realized Gains (Losses) On Investments, Increase (Decrease) In Taxable Income Triggering Event [Domain] Triggering Event [Domain] Triggering Event Derivative Contract [Domain] Derivative Contract [Domain] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Axis] Spartan Energy Services, LLC Spartan Energy Services, LLC [Member] Spartan Energy Services, LLC Net Reductions to Subordinated Structured Notes and related investment cost Net Reductions to Subordinated Structured Notes and Related Investment Cost Net Reductions to Subordinated Structured Notes and Related Investment Cost Increase (decrease) in due to broker Increase (Decrease) in Payable to Broker-Dealer and Clearing Organization Realized loss Realized Investment Gains (Losses) Employee Stock Option Share-Based Payment Arrangement, Option [Member] Purchases of portfolio investments Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases Enseo Acquisition, Inc. Enseo Acquisition, Inc. [Member] Enseo Acquisition, Inc. Additional 402(v) Disclosure Additional 402(v) Disclosure [Text Block] Asset Class [Axis] Asset Class [Axis] Related Party [Domain] Related and Nonrelated Parties [Domain] Series A5 Shares [Member] Series A5 Shares 3.437% 2028 Notes 3.437 2028 Notes [Member] 3.437 2028 Notes Tabular List, Table Tabular List [Table Text Block] Received cash at closing Restricted Cash and Cash Equivalent, Noncurrent Paid-in capital in excess of par (Notes 9 and 12) Additional Paid in Capital Floating Rate Preferred Stock Floating Rate Preferred Stock [Member] Floating Rate Preferred Stock 6.375% 2024 Notes 6.375 2024 Notes [Member] 6.375 2024 Notes Members of Nationwide Management Members of Nationwide Management [Member] Members of Nationwide Management Name Awards Close in Time to MNPI Disclosures, Individual Name Average outstanding balance Line of Credit Facility, Average Outstanding Amount Investment, Identifier [Axis] Investment, Identifier [Axis] Entertainment Entertainment Sector [Member] Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested [Member] Number of asset going through foreclosure Investment Transactions, Number of Asset Going Through Foreclosure Investment Transactions, Number of Asset Going Through Foreclosure Enterprise value waterfall (Market approach) Valuation, Market Approach [Member] Discovery MSO Holdco, LLC. Discovery MSO Holdco, LLC. [Member] Discovery MSO Holdco, LLC. Third Exchange Third Exchange [Member] Third Exchange CP Energy Services Inc. CP Energy Services Inc. [Member] CP Energy Services Inc. Preferred Stock, par value $0.001 per share (764,723,593 and 766,678,529 shares of preferred stock authorized; 67,450,547 and 68,468,200 issued and outstanding, respectively) (Note 9) Preferred Stock, Value, Issued Adjustment to Compensation: Adjustment to Compensation [Axis] (Increase) decrease in due from broker Increase (Decrease) in Receivable from Broker-Dealer and Clearing Organization 8.95% 2031 Notes 8.95% 2031 Notes [Member] 8.95% 2031 Notes Cost basis, gross additions Investments Owned, At Cost, Gross Additions Investments Owned, At Cost, Gross Additions Credit Concentration Risk Credit Concentration Risk [Member] Rule 10b5-1 Arrangement Terminated Rule 10b5-1 Arrangement Terminated [Flag] Aggregate Erroneous Compensation Amount Aggregate Erroneous Compensation Amount Cash paid for interest Interest Paid, Excluding Capitalized Interest, Operating Activity Investment Management Agreement - Incentive Rate, Realized Capital Gains Investment Management Agreement - Incentive Rate, Realized Capital Gains [Member] Investment Management Agreement - Incentive Rate, Realized Capital Gains Hedging Designation [Axis] Hedging Designation [Axis] Shares issued through reinvestment of dividends Temporary Equity, Value, Dividend Reinvestment Plan Temporary Equity, Value, Dividend Reinvestment Plan Credit Facility [Axis] Credit Facility [Axis] Royalty, net profit and revenue interests Royalty, Net Profit and Net Revenue Interests Royalty, Net Profit and Net Revenue Interests Total Foreign currency forward contracts - Assets Assets, Fair Value Disclosure Name Measure Name Total distributions paid to common stockholders Investment Company, Dividend Distribution And Tax Return Of Capital Distribution Investment Company, Dividend Distribution And Tax Return Of Capital Distribution Pay vs Performance Disclosure [Line Items] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Encinitas Watches Holdco, LLC Encinitas Watches Holdco, LLC [Member] Encinitas Watches Holdco, LLC Debt Instrument [Line Items] Debt Instrument [Line Items] Barracuda Parent, LLC Barracuda Parent, LLC [Member] Barracuda Parent, LLC Paid-in capital in excess of par Additional Paid-in Capital [Member] Other Income Other Income [Text Block] Other Income New WPCC Parent, LLC New WPCC Parent, LLC [Member] New WPCC Parent, LLC Insurance Insurance Sector [Member] Accrued expenses Accrued Liabilities Conversion of preferred stock to common stock Temporary Equity, Value, Conversion of Convertible Securities Temporary Equity, Value, Conversion of Convertible Securities Villages of Wildwood Holdings LLC Villages of Wildwood Holdings LLC [Member] Villages of Wildwood Holdings LLC Interest, net Interest Receivable Interest Receivable Name Trading Arrangement, Individual Name Cash and cash equivalents (restricted cash of $1,986 and $2,812, respectively) Cash and Cash Equivalent Takeout Scenario Valuation Technique, Takeout Scenario [Member] Valuation Technique, Takeout Scenario KM2 Solutions LLC KM2 Solutions LLC [Member] KM2 Solutions LLC Additions Investment Company, Additional Investment Investment Company, Additional Investment Galaxy XV CLO, Ltd. Galaxy XV CLO, Ltd. [Member] Galaxy XV CLO, Ltd. Net Realized and Net Change in Unrealized Gains (Losses) from Investments Debt and Equity Securities, Gain (Loss) Company Selected Measure Amount Company Selected Measure Amount Depreciation and amortization Depreciation, Depletion and Amortization Dividend rate Temporary Equity, Dividend Rate, Percentage Temporary Equity, Dividend Rate, Percentage Net realized (gains) losses from derivative instruments and foreign currency transactions Realized Gain (Loss), Derivative and Foreign Currency Transaction Price Change, Operating, before Tax Elliot Apartments Norcross, LLC Elliot Apartments Norcross, LLC [Member] Elliot Apartments Norcross, LLC Net proceeds of issuance of debt Proceeds From Issuance of Unsecured Debt, Net Proceeds From Issuance of Unsecured Debt, Net Members of R-V Industries Management Members of R-V Industries Management [Member] Members of R-V Industries Management Pharmaceuticals Pharmaceuticals Sector [Member] Pharmaceuticals Sector Wright Trucking, Inc. Wright Trucking, Inc. [Member] Wright Trucking, Inc. Investment Advisory Agreement Investment Advisory Agreement [Member] Investment Advisory Agreement Net unrealized (gains) losses on investments Investment Company, Tax Basis, Unrealized (Gain) Loss, Not Currently (Taxable) Deductible Investment company, distributable earnings (loss), accumulated long-term capital gain Investment Company, Distributable Earnings (Loss), Accumulated Long-Term Capital Gain (Loss) Non-PEO NEO Non-PEO NEO [Member] RGIS Services, LLC RGIS Services, LLC [Member] RGIS Services, LLC Temporary Equity, by Class of Stock [Table] Temporary Equity, by Class of Stock [Table] Award Timing Method Award Timing Method [Text Block] Forgone Recovery, Explanation of Impracticability Forgone Recovery, Explanation of Impracticability [Text Block] Share repurchase increase in authorized amount Share Repurchase Program, Increase In Authorized Amount Share Repurchase Program, Increase In Authorized Amount NPRC Apex Holdings LLC NPRC Apex Holdings LLC [Member] NPRC Apex Holdings LLC Reclassification of distributions from capital, increase (decrease) Investment Company, Tax Reclassification, Increase (Decrease) Currency Purchased Notional Amount to be Sold Derivative Liability, Notional Amount Belnick Holdings of Delaware, LLC Belnick Holdings of Delaware, LLC [Member] Belnick Holdings of Delaware, LLC Net Increase (Decrease) in Net Assets Resulting from Operations Net Increase (Decrease) in Net Assets Resulting from Operations Net increase (decrease) in net assets resulting from operations Net Income (loss) Net Income (Loss) Attributable to Parent Long-Term Debt, Type [Axis] Long-Term Debt, Type [Axis] Erroneous Compensation Analysis Erroneous Compensation Analysis [Text Block] Investments Investments [Member] Restatement Determination Date: Restatement Determination Date [Axis] Per Share Data Investment Company, Per Share Data [Abstract] Investment Company, Per Share Data Litigation settlement Litigation Settlement, Amount Awarded to Other Party Healthcare Venture Partners, LLC Healthcare Venture Partners, LLC [Member] Healthcare Venture Partners, LLC Threshold consecutive trading days Debt Instrument, Convertible, Threshold Consecutive Trading Days Payment-in-kind interest Fair Value, Measurement With Unobservable Inputs Reconciliation, Recurring Basis, Asset, Additions For Paid-In-Kind interest Fair Value, Measurement With Unobservable Inputs Reconciliation, Recurring Basis, Asset, Additions For Paid-In-Kind interest Investment Income Revenues [Abstract] Permanent differences Investment, Tax Basis Reconciliation, Permanent Differences, Increase (Decrease) In Taxable Income Investment, Tax Basis Reconciliation, Permanent Differences, Increase (Decrease) In Taxable Income Collateral posted Collateral Already Posted, Aggregate Fair Value Accumulated Realized Losses Accumulated Realized Losses [Member] Accumulated Realized Losses Tobacco Tobacco Sector [Member] Tobacco Sector Pension Benefits Adjustments, Footnote Pension Benefits Adjustments, Footnote [Text Block] Safety Solutions Financing, LLC Safety Solutions Financing, LLC [Member] Safety Solutions Financing, LLC Other Income Other Income Policy [Policy Text Block] Other Income Policy Statistical Measurement [Domain] Statistical Measurement [Domain] Repurchase program, authorized amount (in shares) Temporary Equity, Repurchase Program, Authorized, Number of Shares Temporary Equity, Repurchase Program, Authorized, Number of Shares Document Fiscal Year Focus Gross Amounts Offset in the Consolidated Statement of Assets and Liabilities Derivative Liability, Subject to Master Netting Arrangement, Asset Offset 7.50% Preferred Stock 7.50% Preferred Stock [Member] 7.50% Preferred Stock Option Pricing Model Valuation Technique, Option Pricing Model [Member] Structuring, amendment and advisory fees Structuring Fee Advisory Fee Investment Banking, Advisory, Brokerage, and Underwriting Fees and Commissions Authorized and unissued shares of common stock reclassified into shares of preferred stock (in shares) Common Shares Converted Into Preferred Stock, Shares Subscribed but Unissued Common Shares Converted Into Preferred Stock, Shares Subscribed but Unissued Aventiv Technologies, LLC Aventiv Technologies, LLC [Member] Aventiv Technologies, LLC Tender Offer Tender Offer [Member] Tender Offer Common stock, par value $0.001 per share (3,235,276,407 and 1,233,321,471 common shares authorized; 536,295,785 and 512,746,556 issued and outstanding, respectively) (Note 9) Common Stock, Value, Issued Proceeds from settlement of forward contract Proceeds From Settlement Of Forward Contract Proceeds From Settlement Of Forward Contract Mississippi MISSISSIPPI Schedule of Notes Outstanding Schedule of Long-Term Debt Instruments [Table Text Block] Sunbury OH Partners, LLC Sunbury OH Partners, LLC [Member] Sunbury OH Partners, LLC Terraces at Perkins Rowe JV LLC Terraces at Perkins Rowe JV LLC [Member] Terraces at Perkins Rowe JV LLC O 2027 M6 Dividends O 2027 M6 Dividends [Member] O 2027 M6 Dividends Credit Facility Line of Credit [Member] Restatement Determination Date Restatement Determination Date 2019 Notes 2019 Notes [Member] 2019 Notes Cash collateral Derivative Asset, Subject to Master Netting Arrangement, Collateral, Obligation to Return Cash, Offset Against Derivative Asset Valley Electric Holdings I, Inc. Valley Electric Holdings I, Inc. [Member] Valley Electric Holdings I, Inc. 2022 Notes 2022 Notes [Member] 2022 Notes Building Products Building Products Sector [Member] Building Products Sector 2029 Notes 2029 Notes [Member] 2029 Notes Credit.com Holdings, LLC Credit.com Holdings, LLC [Member] Credit.com Holdings, LLC Non-control/non-affiliate investments Investment, Unaffiliated Issuer [Member] Preventics, Inc. (d/b/a Legere Pharmaceuticals) Preventics, Inc. (d/b/a Legere Pharmaceuticals) [Member] Preventics, Inc. (d/b/a Legere Pharmaceuticals) Investments Held Benchmark Investments Held Benchmark [Member] Investments Held Benchmark Amendment Flag Proceeds from equity method investments Proceeds from Sale of Equity Method Investments Health Care Providers & Services Health Care Providers and Services Sector [Member] Health Care Providers and Services Sector Net Investment Income Net Investment Income Investment company, distributable earnings (loss), accumulated ordinary income Investment Company, Distributable Earnings (Loss), Accumulated Ordinary Income (Loss) NPRC Rutland LLC NPRC Rutland LLC [Member] NPRC Rutland LLC Investments [Domain] Investments [Domain] Increase (decrease) in due to Prospect Capital Management Increase (Decrease) in Management Fee Payable Outstanding shares threshold Outstanding Shares Threshold Outstanding Shares Threshold Interest accrued at cash interest rate Interest Accrued at Cash Interest Rate Interest Accrued at Cash Interest Rate Repurchase of Preferred Stock Temporary Equity, Repurchase of Preferred Stock Temporary Equity, Repurchase of Preferred Stock 5224 Long Road Holdings, LLC 5224 Long Road Holdings, LLC [Member] 5224 Long Road Holdings, LLC Adjustment to Non-PEO NEO Compensation Footnote Adjustment to Non-PEO NEO Compensation Footnote [Text Block] Transfers into Level 3 Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3 Help/Systems Holdings, Inc. (d/b/a Forta, LLC) Help/Systems Holdings, Inc. [Member] Help/Systems Holdings, Inc. Entity Address, State or Province Aerospace & Defense Aerospace Sector [Member] PEO Total Compensation Amount PEO Total Compensation Amount Investment Advisory And Management Agreement Incentive Rate Annual Hurdle Rate Investment Advisory And Management Agreement Incentive Rate Annual Hurdle Rate [Member] Investment Advisory And Management Agreement Incentive Rate Annual Hurdle Rate Specialty Retail Specialty Retail Sector [Member] Specialty Retail Sector Number of board of directors appointed Number of Board of Directors Appointed Number of Board of Directors Appointed Basic (in shares) Weighted average common shares outstanding - basic (in shares) Weighted average shares of common stock outstanding (in shares) Weighted Average Number of Shares Outstanding, Basic Asset coverage ratio on our senior security stock Investment Company, Senior Security, Stock, Asset Coverage Ratio Recovery Solutions Parent, LLC Recovery Solutions Parent, LLC [Member] Recovery Solutions Parent, LLC Prospect Capital InterNotes® Prospect Capital InterNotes [Member] Prospect Capital InterNotes Residential Real Estate Investment Trusts (REITs) Equity Real Estate Investment Trusts (REITs) Sector [Member] Equity Real Estate Investment Trusts (REITs) Sector Series A Cumulative Non-Voting Preferred Stock Series A Cumulative Non-Voting Preferred Stock [Member] Series A Cumulative Non-Voting Preferred Stock Schedule of Investments [Abstract] Credit Central of Texas, LLC Credit Central of Texas, LLC [Member] Credit Central of Texas, LLC Net of revenues Investment Owned, Percent of Net Revenues Investment Owned, Percent of Net Revenues Investment Company, Nonconsolidated Subsidiary [Line Items] Investment Company, Nonconsolidated Subsidiary [Line Items] June 15, 2029 – July 15, 2029 Debt Instrument Redemption Period Eighteen [Member] Debt Instrument Redemption Period Eighteen MAC Discount, LLC Mac Discount LLC [Member] Mac Discount LLC (Increase) decrease in interest receivable, net Increase (Decrease) in Accrued Interest Receivable, Net Ordinary income Investment Company, Distribution, Ordinary Income Media Media Sector [Member] Media Sector Victor Holdings Victor Holdings [Member] Victor Holdings Document Information [Line Items] Award Timing MNPI Disclosure Award Timing MNPI Disclosure [Text Block] 23741 Pond Road Owner, LLC 23741 Pond Road Owner, LLC [Member] 23741 Pond Road Owner, LLC Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Class of Stock [Axis] O 2027 M8 Dividends O 2027 M8 Dividends [Member] O 2027 M8 Dividends Debt issuance costs, gross Debt Issuance Costs, Gross Net Increase (Decrease) in Net Assets Resulting from Operations applicable to Common Stockholders Net increase (decrease) in net assets resulting from operations - basic Net Income (Loss) Available to Common Stockholders, Basic Shares issued through reinvestment of dividends Stock Issued During Period, Value, Dividend Reinvestment Plan Maximum borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity National Property REIT Corp. NPRC National Property REIT Corp. [Member] National Property REIT Corp. Portfolio Investments Schedule of Investments [Text Block] Investment owned, discount (premium) Investment Owned, Discount (Premium) Investment Owned, Discount (Premium) Purchase Price SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Gross BCPE Osprey Buyer, Inc. BCPE Osprey Buyer, Inc. [Member] BCPE Osprey Buyer, Inc. Overallotment purchase option term Overallotment Purchase Option Term Overallotment Purchase Option Term First Lien Revolving Line of Credit Debt Securities, First Lien Revolving Line of Credit [Member] Debt Securities, First Lien Revolving Line of Credit PIK Rate - Capitalized Investment, Interest Rate, Paid in Kind Capitalized Investment, Interest Rate, Paid in Kind Capitalized Total Operating Expenses Operating expenses Investment Income, Investment Expense Recent Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Per Share Information Earnings Per Share, Policy [Policy Text Block] Annualized ratio of operating expenses to average net assets applicable to common shares Investment Company, Expense Ratio before Incentive Allocation Amortization of deferred financing costs Amortization of Debt Issuance Costs Unsecured Debt Unsecured Debt [Member] Automobile Components Automobile Components Sector [Member] Automobile Components Sector (Increase) decrease in due from Affiliate Increase (Decrease) Due from Affiliates Total Amount Outstanding Net Carrying Value Total Amount Outstanding Long-Term Debt Value of shares issued through reinvestment of dividends (in shares) Shares issued through reinvestment of dividends (in shares) Stock Issued During Period, Shares, Dividend Reinvestment Plan Equity Awards Adjustments, Excluding Value Reported in Compensation Table Equity Awards Adjustments, Excluding Value Reported in the Compensation Table [Member] Gross Amounts of Cash Collateral Received (Pledged) from Counterparty Not Offset in Consolidated Statements of Assets and Liabilities Derivative Asset, Subject to Master Netting Arrangement, Collateral, Obligation to Return Cash Not Offset Conversion of Stock, Name [Domain] Conversion of Stock, Name [Domain] Beginning balance, Preferred Stock Classified as Temporary Equity (in shares) Ending balance, Preferred Stock Classified as Temporary Equity (in shares) Temporary equity, shares outstanding (in shares) Preferred Stock Outstanding (in shares) Temporary Equity, Shares Outstanding Security Exchange Name Preventics, Inc. (d/b/a Legere Pharmaceuticals) Preventics, Inc. [Member] Preventics, Inc. Common Equity/Interests/Warrants 9 Common Stock, Interests Or Warrants9 [Member] Common Stock, Interests Or Warrants9 BCPE North Star US Holdco 2, Inc. BCPE North Star US Holdco 2, Inc. [Member] BCPE North Star US Holdco 2, Inc. O 2027 M4 Dividends O 2027 M4 Dividends [Member] O 2027 M4 Dividends Prospect Administration Prospect Administration [Member] Prospect Administration Newly-Issued Series M5 Preferred Stock Newly-Issued Series M5 Preferred Stock [Member] Newly-Issued Series M5 Preferred Stock Valuation Approach and Technique [Axis] Valuation Approach and Technique [Axis] Total Foreign currency forward contracts - Liabilities Liabilities, Fair Value Disclosure O 2027 Q1 Dividends O 2027 Q1 Dividends [Member] O 2027 Q1 Dividends Total increase (decrease) during period Stockholders' Equity, Period Increase (Decrease) Directors’ fees Director Fee Segment Reporting Segment Reporting, Policy [Policy Text Block] Statement of Comprehensive Income [Abstract] First Lien Term Loan Receivable First Lien Term Loan Receivable [Member] First Lien Term Loan Receivable Preferred Equity Preferred Equity [Member] Preferred Equity Name Outstanding Recovery, Individual Name Award Timing, How MNPI Considered Award Timing, How MNPI Considered [Text Block] Debt Securities, First Lien 11 Debt Securities, First Lien 11 [Member] Debt Securities, First Lien 11 Schedule of Weighted Average Number of Shares Schedule of Weighted Average Number of Shares [Table Text Block] Foster Testing Co., Inc. Foster Testing Co., Inc. [Member] Foster Testing Co., Inc. Follow-On Acquisitions (Excluding initial investment cost) Investment Owned, Cumulative Follow-On Additions Investment Owned, Cumulative Follow-On Additions Credit Central Loan Company, LLC Credit Central Loan Company, LLC [Member] Credit Central Loan Company, LLC Geographical [Domain] Geographical [Domain] Capstone Logistics Acquisition, Inc. Capstone Logistics Acquisition, Inc. [Member] Capstone Logistics Acquisition, Inc. Newly-Issued Series M4 Preferred Stock Newly-Issued Series M4 Preferred Stock [Member] Newly-Issued Series M4 Preferred Stock Burgess Point Purchaser Corporation Burgess Point Purchaser Corporation [Member] Burgess Point Purchaser Corporation Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year [Member] Pension Adjustments Prior Service Cost Pension Adjustments Prior Service Cost [Member] Schedule of Investments [Table] Schedule of Investments [Table] Unrealized losses Investment, Tax Basis, Unrealized Loss Structuring fees Other Income, Structuring Fees Other Income, Structuring Fees Maximum Aggregate Liquidation Preference of Offering Temporary Equity, Liquidation Preference OneTouchPoint Corp OneTouchPoint Corp [Member] OneTouchPoint Corp Outstanding amount Principal Outstanding Total Long-Term Debt, Gross Asset Class [Domain] Asset Class [Domain] Related Party Transactions [Abstract] 1 Month SOFR 1 Month SOFR [Member] 1 Month SOFR Echelon Transportation, LLC Echelon Transportation, LLC [Member] Echelon Transportation, LLC Shares issued (in shares) Shares, Issued Compensation Amount Outstanding Recovery Compensation Amount Jackson Pear Orchard LLC Jackson Pear Orchard LLC [Member] Jackson Pear Orchard LLC Individual: Individual [Axis] Diluted (in shares) Weighted average shares of common stock outstanding - diluted (in shares) Weighted Average Number of Shares Outstanding, Diluted Total Investments Concentration Risk Total Investments Concentration Risk [Member] Total Investments Concentration Risk Entity Emerging Growth Company Related Party Transaction [Line Items] Related Party Transaction [Line Items] Derivative Instruments Derivatives, Policy [Policy Text Block] Underlying Security Market Price Change Underlying Security Market Price Change, Percent Research Now Group, LLC and Dynata, LLC Research Now Group, LLC and Dynata, LLC [Member] Research Now Group, LLC and Dynata, LLC Market yield Measurement Input, Market Yield [Member] Measurement Input, Market Yield Derivative Instruments Derivative Instruments and Hedging Activities Disclosure [Text Block] More Than 35% and An Amount Less Than or Equal to 60% Credit Facility, Usage, More Than 35% and An Amount Less Than or Equal to 60% [Member] Credit Facility, Usage, More Than 35% and An Amount Less Than or Equal to 60% Royalty, net profit and revenue interests Royalty Profit Interest, Other Income Royalty Profit Interest, Other Income Prepaid expenses Prepaid Expense Gross Amounts of Recognized Assets (Liabilities) Derivative Liability, Subject to Master Netting Arrangement, before Offset Other Other Receivables Other Receivables Other Receivables Other Receivables SPCP Edge CL Owner LLC SPCP Edge CL Owner LLC [Member] SPCP Edge CL Owner LLC Wright Foster Disposals, LLC Wright Foster Disposals, LLC [Member] Wright Foster Disposals, LLC Investment Advisory And Management Agreement Incentive Rate Pre Incentive Fee Net Investment Income Exceeds Catch Up Threshold Member Investment Advisory And Management Agreement Incentive Rate Pre Incentive Fee Net Investment Income Exceeds Catch Up Threshold [Member] Investment Advisory And Management Agreement Incentive Rate Pre Incentive Fee Net Investment Income Exceeds Catch Up Threshold Vessel Company II, LLC Vessel Company II, LLC [Member] Vessel Company II, LLC Proceeds from issuance of preferred stock, net of underwriting costs Proceeds from Issuance of Redeemable Preferred Stock Redemptions of Prospect Capital InterNotes®, net (Note 7) Repayments of unsecured debt Repayments of Unsecured Debt 3.364% 2026 Notes 3.364 2026 Notes [Member] 3.364 2026 Notes O 2026 M2 Dividends O 2026 M2 Dividends [Member] O 2026 M2 Dividends Hotels, Restaurants & Leisure Hotels, Restaurants & Leisure Sector [Member] Hotels, Restaurants & Leisure Sector Issuances of Prospect Capital InterNotes® (Note 7) Principal Amount Proceeds from Issuance of Unsecured Debt Investment Company, Net Assets [Roll Forward] Investment Company, Net Assets [Roll Forward] Organization, Consolidation and Presentation of Financial Statements [Abstract] Currency Sold Notional Amount to be Purchased Derivative Asset, Notional Amount Terminal Cap Rate Measurement Input, Cap Rate [Member] Investment Company, Financial Highlights [Line Items] Investment Company, Financial Highlights [Line Items] Annualized ratio of net investment income to average net assets applicable to common shares Investment Company, Investment Income (Loss) Ratio Credit Facility, Usage [Axis] Credit Facility, Usage [Axis] Credit Facility, Usage All Executive Categories All Executive Categories [Member] Debt Securities, Second Lien 2 Debt Securities, Second Lien2 [Member] Debt Securities, Second Lien2 Valuation Approach and Technique [Domain] Valuation Approach and Technique [Domain] Common Equity Common Equity [Member] Common Equity Pension Adjustments Service Cost Pension Adjustments Service Cost [Member] Principal payments under Revolving Credit Facility (Note 4) Repayments of Long-Term Lines of Credit Schedule of Subsidiary of Limited Liability Company or Limited Partnership [Table] Subsidiary of LLC or LP [Table] Lakepoint OH Partners, LLC Lakepoint OH Partners, LLC [Member] Lakepoint OH Partners, LLC HarbourView CLO VII-R, Ltd. HarbourView CLO VII-R, Ltd. [Member] HarbourView CLO VII-R, Ltd. Asset coverage ratio Investment Company, Senior Security, Indebtedness, Asset Coverage Ratio Collateralized financings Collateralized Financings LCM XIV Ltd. LCM XIV Ltd. [Member] LCM XIV Ltd. Hamptons Apartments Owner, LLC Hamptons Apartments Owner, LLC [Member] Hamptons Apartments Owner, LLC Schedule of Earnings Per Share, Basic and Diluted Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Jefferson Chase OH Partners, LLC Jefferson Chase OH Partners, LLC [Member] Jefferson Chase OH Partners, LLC Total assets at fair value are in non-accrual status Fair Value, Investments, Non-Accrual Status of Total Assets Fair Value, Investments, Non-Accrual Status of Total Assets Debt Disclosure [Abstract] Investment Company, Nonconsolidated Subsidiary [Domain] Investment Company, Nonconsolidated Subsidiary [Domain] Segment Reporting Segment Reporting [Text Block] Minimum Minimum [Member] Investment Type [Axis] Investment Type [Axis] Investment Advisory And Management Agreement Incentive Rate Pre Incentive Fee Net Investment Income Below Catch Up Threshold Investment Advisory And Management Agreement Incentive Rate Pre Incentive Fee Net Investment Income Below Catch Up Threshold [Member] Investment Advisory And Management Agreement Incentive Rate Pre Incentive Fee Net Investment Income Below Catch Up Threshold Income Taxes [Line Items] Income Taxes [Line Items] Income Taxes [Line Items] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Common Equity/Interests/Warrants 5 Common Stock, Interests Or Warrants5 [Member] Common Stock, Interests Or Warrants5 Liabilities  Liabilities [Abstract] Schedule of Subsidiary of Limited Liability Company Schedule of Subsidiary of Limited Liability Company or Limited Partnership [Table Text Block] Schedule of Subsidiary of Limited Liability Company or Limited Partnership Effect of foreign currency exchange rates Effect of Exchange Rate on Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Weighted-average shares of common stock outstanding (Note 11) Weighted Average Number of Shares Outstanding Reconciliation [Abstract] Non-Rule 10b5-1 Arrangement Adopted Non-Rule 10b5-1 Arrangement Adopted [Flag] Series A5 Series A5 7.50% Series A5 Preferred Stock [Member] 7.50% Series A5 Preferred Stock QC Holdings TopCo, LLC QC Holdings TopCo, LLC [Member] QC Holdings TopCo, LLC Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table [Member] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Online Lending Online Lending Sector [Member] Online Lending Sector Other liabilities Other Liabilities Amount Distributed Dividends, Common Stock Common stock, shares authorized (in shares) Common Stock, Shares Authorized Schedule Issued Notes Schedule of Debt Issued [Table Text Block] Schedule of Debt Issued First Tower Finance Company LLC First Tower Finance Company LLC [Member] First Tower Finance Company LLC Schedule of Carrying Values and Estimated Fair Values of Debt Instruments Schedule of Carrying Values and Estimated Fair Values of Debt Instruments [Table Text Block] Exercise Price Award Exercise Price Stock repurchase program, authorized amount Share Repurchase Program, Authorized, Amount Document Quarterly Report Air Freight & Logistics Air Freight & Logistics Sector [Member] Air Freight & Logistics Sector Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested [Member] Senior Subordinated Notes Senior Subordinated Notes [Member] Common Equity/Interests/Warrants 4 Common Stock, Interests Or Warrants4 [Member] Common Stock, Interests Or Warrants4 Maximum annualized dividend rate Temporary Equity, Maximum Annualized Dividend Rate Temporary Equity, Maximum Annualized Dividend Rate Shoes West, LLC (d/b/a Taos Footwear) Shoes West, LLC (d/b/a Taos Footwear) [Member] Shoes West, LLC (d/b/a Taos Footwear) Input Investment Company, Investment Owned, Measurement Input Investments, cost Investment , cost Cost Investment Owned, Cost Vessel Company III, LLC Vessel Company III, LLC [Member] Vessel Company III, LLC Gross Additions (Cost) Investments in and Advances to Affiliates, at Fair Value, Gross Additions Interest payable Interest Payable Repayments of long-term debt Repayments of Long-Term Debt Senior securities coverage per unit, including unfunded commitments (in dollars per share) Senior Securities Coverage Per Unit, Including Unfunded Commitments Senior Securities Coverage Per Unit, Including Unfunded Commitments Involuntary Liquidating Preference per Unit (in dollars per unit) Preferred stock, liquidation preference (usd per share) Base management fee (Note 13) Base management fee Management Fee Expense Incentive fee expense, capital-gain-based Incentive Fee Expense, Capital-Gain-Based Unamortized discount and debt issuance costs Unamortized debt issuance Unamortized Discount & Debt Issuance Costs Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net Household Durables Household Durables Sector [Member] Household Durables Sector Debt Securities, Second Lien 1 Debt Securities, Second Lien1 [Member] Debt Securities, Second Lien1 Qualifying assets Qualifying Assets Qualifying Assets Awards Close in Time to MNPI Disclosures, Table Awards Close in Time to MNPI Disclosures [Table Text Block] Financial Highlights Investment Company, Financial Highlights [Text Block] (Increase) decrease in other receivables Increase (Decrease) in Other Receivables Equity Component [Domain] Equity Component [Domain] Measurement Input Type [Domain] Measurement Input Type [Domain] Exchanges (in shares) Temporary Equity, Shares, Exchanges Temporary Equity, Shares, Exchanges Payments for purchases of investments Payment for Purchase, Investment, Operating Activity MITY FSC, Inc. MITY FSC, Inc. [Member] MITY FSC, Inc. Adoption Date Trading Arrangement Adoption Date 3 Month SOFR 3 Month SOFR [Member] 3 Month SOFR Counterparty Name [Domain] Counterparty Name [Domain] Due to broker Broker-Dealer, Payable to Other Broker-Dealer and Clearing Organization Scenario, Plan Scenario, Plan [Member] Personal Care Products Personal Care Products Sector [Member] Personal Care Products Sector Term Loan B Term Loan B [Member] Term Loan B Title Trading Arrangement, Individual Title Forgone Recovery due to Disqualification of Tax Benefits, Amount Forgone Recovery due to Disqualification of Tax Benefits, Amount NPRC Twin Oaks LLC NPRC Twin Oaks LLC [Member] NPRC Twin Oaks LLC Apidos CLO XV Apidos CLO XV [Member] Apidos CLO XV Accounting Policies [Abstract] Restatement does not require Recovery Restatement Does Not Require Recovery [Text Block] % of Net Assets Derivative, Net Assets, Percentage Total interest income (Note 2) Interest Income Interest Income Interest Income, Operating Insider Trading Policies and Procedures Adopted Insider Trading Policies and Procedures Adopted [Flag] Credit Central, LLC Credit Central, LLC [Member] Credit Central, LLC Goldenstrand OH Partners, LLC Goldenstrand OH Partners, LLC [Member] Goldenstrand OH Partners, LLC Schedule of Average Rate and Outstanding Balance Schedule of Line of Credit Facilities [Table Text Block] Stock repurchase program, number of shares authorized to be repurchased (in shares) Share Repurchase Program, Authorized, Number of Shares Per Fiscal Quarter Per Fiscal Quarter [Member] Per Fiscal Quarter Less Than 35% or Equal to 35% Credit Facility, Usage, Less Than 35% or Equal to 35% [Member] Credit Facility, Usage, Less Than 35% or Equal to 35% Repayments of Debt Repayments of Debt Net change in unrealized gain (losses) Debt and Equity Securities, Net Change In Unrealized Gain (Loss) Debt and Equity Securities, Net Change In Unrealized Gain (Loss) TP Kokomo, LLC TP Kokomo, LLC [Member] TP Kokomo, LLC Olentangy Commons Owner LLC Olentangy Commons Owner LLC [Member] Olentangy Commons Owner LLC Eyefive, LLC (d/b/a Shipoffers) Eyefive, LLC (d/b/a Shipoffers) [Member] Eyefive, LLC (d/b/a Shipoffers) Litigation Commitments and Contingencies Disclosure [Text Block] Compensation Actually Paid vs. Net Income Compensation Actually Paid vs. Net Income [Text Block] Market price threshold Market Price Threshold Market Price Threshold Weighted Average Weighted Average [Member] Taco Bell, OK Taco Bell, OK [Member] Taco Bell, OK All Adjustments to Compensation All Adjustments to Compensation [Member] NPRC Fairburn LLC NPRC Fairburn LLC [Member] NPRC Fairburn LLC Name of Property [Domain] Name of Property [Domain] Preferred stock, liquidation value Preferred Stock, Liquidation Preference, Value Federal and State Income Taxes and Taxable Subsidiaries Income Tax, Policy [Policy Text Block] Net Cash Provided by (Used in) Operating Activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Common stock transactions (in dollars per share) Investment Company, Common Stock Transactions, Per Share Investment Company, Common Stock Transactions, Per Share PeopleConnect Holdings, Inc PeopleConnect Holdings, Inc [Member] PeopleConnect Holdings, Inc Total increase (decrease) Temporary Equity, Carrying Amount, Period Increase (Decrease) Income Statement [Abstract] Document Transition Report Operating Expenses Operating Expenses [Abstract] Repayment of loan Proceeds from Collection of Notes Receivable Valley Electric Company, Inc. Valley Electric Company, Inc. [Member] Valley Electric Company, Inc. Stock Appreciation Rights (SARs) Stock Appreciation Rights (SARs) [Member] Unrealized gains Investment, Tax Basis, Unrealized Gain Basis spread rate Investment, Basis Spread, Variable Rate City Area Code Triggering Event [Axis] Triggering Event [Axis] Triggering Event NPRC Taylors LLC NPRC Taylors LLC [Member] NPRC Taylors LLC Geographic Concentration Risk Geographic Concentration Risk [Member] Document Information [Table] Subsequent Events Subsequent Events [Text Block] Expected volatility Measurement Input, Price Volatility [Member] Name Forgone Recovery, Individual Name Debt Repayment Condition [Domain] Debt Repayment Condition [Domain] Debt Repayment Condition [Domain] Non-GAAP Measure Description Non-GAAP Measure Description [Text Block] July 15, 2036 – February 15, 2037 Debt Instrument Redemption Period Twenty One [Member] Debt Instrument Redemption Period Twenty One Preferred equity ownership interest Limited Liability Company or Limited Partnership, Members or Limited Partners, Preferred Equity Ownership Interest Limited Liability Company or Limited Partnership, Members or Limited Partners, Preferred Equity Ownership Interest Entity [Domain] VTI Acquisition, Inc VTI Acquisition, Inc [Member] VTI Acquisition, Inc Per share market value at end of year (in dollars per share) Investment Company, Market Value, Per Share Preferred stock, shares issued (in shares) Preferred Stock, Shares Issued Distributions received, or entitled to be received, Investment Owned, Distribution Received and Receivable Investment Owned, Distribution Received and Receivable Accordion feature, increase limit Line of Credit Facility, Increase in Credit Limit Line of Credit Facility, Increase in Credit Limit Follow-On Investments (NPRC Common Stock, excluding cost of initial investment) Investment Owned, Follow-On Additions Investment Owned, Follow-On Additions Conversion of preferred stock to common stock Conversion of Stock, Amount Converted Number of parts to incentive fee Related Party Transaction, Number Of Components Related Party Transaction, Number Of Components Per Calendar Month Per Calendar Month [Member] Per Calendar Month Shares issued (in shares) Stock Issued During Period, Shares, New Issues Principal amount Investment Owned, Balance, Principal Amount Preferred stock, conversion ratio Preferred Stock, Convertible, Conversion Ratio Gross Amounts Offset in the Consolidated Statement of Assets and Liabilities Derivative Asset, Subject to Master Netting Arrangement, Liability Offset Lorring Owner LLC Lorring Owner LLC [Member] Lorring Owner LLC Cost basis of investments for tax purposes Investment, Tax Basis, Cost Issuable to Common Stock Holders Pursuant to Dividend Reinvestment and Direct Stock Purchase Plans Issuable to Common Stock Holders Pursuant to Dividend Reinvestment and Direct Stock Purchase Plans [Member] Issuable to Common Stock Holders Pursuant to Dividend Reinvestment and Direct Stock Purchase Plans Help/Systems Holdings, Inc. (d/b/a Forta, LLC) Help/Systems Holdings, Inc. (d/b/a Forta, LLC) [Member] Help/Systems Holdings, Inc. (d/b/a Forta, LLC) Fair Value Measurement Inputs and Valuation Techniques [Line Items] Fair Value Measurement Inputs and Valuation Techniques [Line Items] Schedule of Reconciliation of Net Increase in Net Assets Resulting from Operations to Taxable Income Federal Income Tax Note [Table Text Block] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Revision of Prior Period [Domain] Revision of Prior Period [Domain] Change of control triggering event threshold Change of Control Triggering Event Threshold Change of Control Triggering Event Threshold Investment Company [Abstract] 1st Lien Term Loan Debt Securities, 1st Lien Term Loan [Member] Debt Securities, 1st Lien Term Loan Erroneously Awarded Compensation Recovery Erroneously Awarded Compensation Recovery [Table] Series A1, Series M1, Series M2, Series A3, Series M3, Series A4, and Series M4 shares Series A1, Series M1, and Series M2, Series A3, Series M3, Series A4, and Series M4, And Series A5, and Series M5 [Member] Series A1, Series M1, and Series M2, Series A3, Series M3, Series A4, and Series M4, And Series A5, and Series M5 Schedule of Unobservable Inputs Used in Fair Value Measurement of Level 3 Investments Fair Value Measurement Inputs and Valuation Techniques [Table Text Block] Revenue Recognition Revenue Recognition, Interest [Policy Text Block] Debt Securities, Second Lien 5 Debt Securities, Second Lien 5 [Member] Debt Securities, Second Lien 5 Software fees incurred Software Fees Incurred Software Fees Incurred Equity securities ownership Equity Securities Ownership Rate Equity Securities Ownership Rate Entity Current Reporting Status Net Cash Provided by (Used in) Financing Activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Control investments Investment, Affiliated Issuer, Controlled [Member] Total Shareholder Return Amount Total Shareholder Return Amount Forward Contracts designated as cash flow hedging instruments Cash Flow Hedging [Member] Total return based on net asset value Investment Company, Total Return Line of Credit Facility [Line Items] Line of Credit Facility [Line Items] Debt Securities, First Lien 5 Debt Securities, First Lien5 [Member] Debt Securities, First Lien5 First Brands Group First Brands Group [Member] First Brands Group Adjustments to reconcile net increase (decrease) in net assets resulting from operations to net cash used in operating activities: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract] 2030 Long-Term Debt, Maturity, Year Three Temporary equity, par value (usd per share) Temporary Equity, Par or Stated Value Per Share Financing Activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract] Net increase (decrease) in preferred dividend accrual Temporary Equity, Net Decrease In Preferred Dividend Accrual Temporary Equity, Net Decrease In Preferred Dividend Accrual Maturity Date Range Three Debt Instrument, Redemption, Period Three [Member] Unused capacity fee rate Line of Credit Facility, Unused Capacity, Commitment Fee Percentage Town & Country Holdings, Inc. Town & Country Holdings, Inc. [Member] Town & Country Holdings, Inc. Preferred Stock to Common Stock Preferred Stock to Common Stock [Member] Preferred Stock to Common Stock Equity Offerings, Offering Expenses, and Distributions Equity Offerings, Offering Expenses, and Distributions [Text Block] Equity Offerings, Offering Expenses, and Distributions Financial Instruments [Domain] Financial Instruments [Domain] Other comprehensive income (loss): Other Comprehensive Income (Loss), Tax [Abstract] Schedule of Senior Securities Calculated interest basis, days in month Calculated Interest Basis, Days in Month Calculated Interest Basis, Days in Month Shares issued through reinvestment of dividends (in shares) Shares issued through Preferred Stock DRIP (in shares) Temporary Equity, Shares, Dividend Reinvestment Plan Temporary Equity, Shares, Dividend Reinvestment Plan Reimbursement of Administration Expenses (Note 13) Investment Company, Expense Offset Arrangement Total other income (Note 10) Other Income Total Other Income Other Income Derivative Assets, at fair value (Note 6) Derivative Asset Fair Value Gross Fair Value of Recognized Assets Derivative Asset Belnick, LLC (d/b/a The Ubique Group) Belnick, LLC (d/b/a The Ubique Group) [Member] Belnick, LLC (d/b/a The Ubique Group) Public Notes Public Notes [Member] Public Notes Underlying Securities Award Underlying Securities Amount Equity Real Estate Investment Trusts (REITs) Real Estate Sector [Member] Residual Profit, New TLA and TLD Residual Profit, New TLA and TLD Residual Profit, New TLA and TLD Schedule of Financial Highlights Investment Company, Financial Highlights [Table Text Block] Credit Central Holdings of Delaware, LLC Credit Central Holdings of Delaware, LLC [Member] Credit Central Holdings of Delaware, LLC Net change in unrealized (losses) gains Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings, Unrealized Gains (Losses) Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings, Unrealized Gains (Losses) Preferred Stock Preferred Stock [Member] Number of investments held Investment Company, Number Of Investments Held Investment Company, Number Of Investments Held Transfers within Level 3 Fair Value, Measurement With Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers Within Level 3 Fair Value, Measurement With Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers Within Level 3 Marine Transport Marine Transport Sector [Member] Marine Transport Sector O 2027 M1 Dividends O 2027 M1 Dividends [Member] O 2027 M1 Dividends Redstone Holdco 2 LP Redstone Holdco 2 LP [Member] Redstone Holdco 2 LP Schedule of Related Party Transactions, by Related Party [Table] Related Party Transaction [Table] Broda USA, Inc. Broda USA, Inc. [Member] Broda USA, Inc. Apidos CLO XXII Apidos CLO XXII [Member] Apidos CLO XXII Ratios/Supplemental Data Ratios and Supplemental Data [Abstract] Ratios and Supplemental Data Internet & Direct Marketing Retail Internet & Direct Marketing Retail Sector [Member] Internet & Direct Marketing Retail Sector Commitments and Contingencies Disclosure [Abstract] All Trading Arrangements All Trading Arrangements [Member] Other Performance Measure, Amount Other Performance Measure, Amount Award Timing MNPI Considered Award Timing MNPI Considered [Flag] Gain (loss) on derivatives designated as cash flow hedges Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, Tax January 15, 2027 – September 15, 2029 Debt Instrument Redemption Period Fourteen [Member] Debt Instrument Redemption Period Fourteen Mortgage Outstanding SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate First Exchange First Exchange [Member] First Exchange Current Fiscal Year End Date (here only for the Qs) Units (in shares) Investment Owned, Balance, Shares Textiles, Apparel & Luxury Goods Textiles, Apparel & Luxury Goods Sector [Member] Textiles, Apparel & Luxury Goods Sector Non-PEO NEO Average Total Compensation Amount Non-PEO NEO Average Total Compensation Amount Derivative [Line Items] Derivative [Line Items] Atlantis Health Care Group (Puerto Rico), Inc. Atlantis Health Care Group (Puerto Rico), Inc. [Member] Atlantis Health Care Group (Puerto Rico), Inc. Net Amounts Presented in the Consolidated Statement of Assets and Liabilities Derivative Asset, Subject to Master Netting Arrangement, before Offset of Collateral Issuance of preferred stock Temporary Equity, Stock Issued During Period, Value, New Issues Stock repurchased during period (in shares) Stock Repurchased During Period, Shares Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year [Member] Amount ($ per share), common stock (usd per share) Common Stock, Dividends, Per Share, Declared Entity File Number Offering costs from issuance of preferred stock Payments of Stock Issuance Costs of Preferred Stock Payments of Stock Issuance Costs of Preferred Stock Commercial Commercial [Member] Commercial Universal Turbine Parts, LLC Universal Turbine Parts, LLC [Member] Universal Turbine Parts, LLC InterDent, Inc. InterDent, Inc. [Member] InterDent, Inc. Recovery of Erroneously Awarded Compensation Disclosure [Line Items] Second Lien Debt Debt Securities, Second Lien [Member] Debt Securities, Second Lien Measure: Measure [Axis] Series A1 Series A1 5.50% Series A1 Preferred Stock [Member] 5.50% Series A1 Preferred Stock O 2026 M3 Dividends O 2026 M3 Dividends [Member] O 2026 M3 Dividends First Tower Holdings of Delaware LLC First Tower Holdings of Delaware LLC [Member] First Tower Holdings of Delaware LLC Accretion of original issue discount Amortization of Debt Discount (Premium) (Increase) decrease in due from Prospect Administration Increase (Decrease) Due from Other Related Parties January 15, 2031 – April 15, 2031 Debt Instrument Redemption Period Twenty Two [Member] Debt Instrument Redemption Period Twenty Two Net Increase (Decrease) in Net Assets and Temporary Equity Resulting from Operations: Net Income (Loss), Including Portion Attributable to Noncontrolling Interest [Abstract] Equity Components [Axis] Equity Components [Axis] Related Party Related Party [Member] November 15, 2042 – March 15, 2052 Debt Instrument Redemption Period Twenty Five [Member] Debt Instrument Redemption Period Twenty Five Stock Conversion Description [Axis] Stock Conversion Description [Axis] Entity Interactive Data Current Variable Rate [Axis] Variable Rate [Axis] Series A2 Series A2 5.50% Series A2 Preferred Stock [Member] 5.50% Series A2 Preferred Stock Unamortized Discount & Debt Issuance Costs Debt Issuance Costs, Line of Credit Arrangements, Net Entity Small Business Total comprehensive income (loss) Comprehensive Income (Loss), Net of Tax, Attributable to Parent Enterprise value waterfall (Market approach) and Enterprise value waterfall (Discounted cash flow) Valuation, Enterprise Market and Discounted Cash Flow Approach [Member] Valuation, Enterprise Market and Discounted Cash Flow Approach Unamortized discount Debt Instrument, Unamortized Discount Exchanged multiplied (usd per share) Preferred Stock, Dividends, Threshold Multiplied Preferred Stock, Dividends, Threshold Multiplied Investments at Fair Value Investments, At Fair Value [Member] Investments, At Fair Value United Sporting Companies, Inc. United Sporting Companies, Inc. [Member] United Sporting Companies, Inc. TP Stillwater, LLC TP Stillwater, LLC [Member] TP Stillwater, LLC MNPI Disclosure Timed for Compensation Value MNPI Disclosure Timed for Compensation Value [Flag] Paper & Forest Products Paper & Forest Products Sector [Member] Paper & Forest Products Sector Falling Creek Holdings LLC Falling Creek Holdings LLC [Member] Falling Creek Holdings LLC Communications Equipment Communications Equipment Sector [Member] Communications Equipment Sector Proceeds from sale of investments and collection of investment principal Proceeds from Disposition of Investment, Operating Activity Document Type Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Net realized gains (losses) on extinguishment of debt Net realized (gains) losses on extinguishment of debt Net loss on extinguishment of debt Gain (Loss) on Extinguishment of Debt Industry Concentration Risk Industry Concentration Risk [Member] Industry Concentration Risk Net Asset Value Per Common Share (Note 16)  (in dollars per share) Net asset value per common share at beginning of year (in dollars per share) Net asset value per common share at end of year (in dollars per share) Significant Accounting Policies Significant Accounting Policies [Text Block] Food Products Food Products Sector [Member] Food Products Sector Interest at Floating Rates Debt Securities, Floating Interest Rate [Member] Debt Securities, Floating Interest Rate Maximum Current PIK Rate Interest rate, paid in kind Investment, Interest Rate, Paid in Kind Subsequent Event [Line Items] Subsequent Event [Line Items] Statement of Stockholders' Equity [Abstract] Local Phone Number Druid Hills Holdings LLC Druid Hills Holdings LLC [Member] Druid Hills Holdings LLC Transactions with Controlled Companies Additional Financial Information Disclosure [Text Block] Temporary equity, shares authorized (in shares) Temporary Equity, Shares Authorized 2023 Notes 2023 Notes [Member] 2023 Notes Credit Central South, LLC Credit Central South, LLC [Member] Credit Central South, LLC Change in operating assets and liabilities: Increase (Decrease) in Operating Assets [Abstract] Prepayment premium for early repayment Payment for Debt Extinguishment or Debt Prepayment Cost Commitments and Contingencies (Notes 3 and 15) Commitments and Contingencies 5.50% 2030 Notes 5.50% 2030 Notes [Member] 5.50% 2030 Notes Debt Instrument, Redemption, Period [Domain] Debt Instrument, Redemption, Period [Domain] Changed Peer Group, Footnote Changed Peer Group, Footnote [Text Block] Redemption eligibility term Temporary Equity, Redemption Eligibility Temporary Equity, Redemption Eligibility Distributions from earnings Investment Company, Dividend Distribution Gain on repurchase of preferred stock Gain on Repurchase of Preferred Stock Gain on Repurchase of Preferred Stock Floating Rate Preferred Stock Holders Floating Rate Preferred Stock Holders [Member] Floating Rate Preferred Stock Holders Executive Category: Executive Category [Axis] Unsecured Debt Debt Securities, Unsecured Debt [Member] Debt Securities, Unsecured Debt Medical Solutions Holdings, Inc. Medical Solutions Holdings, Inc. [Member] Medical Solutions Holdings, Inc. Counterparty Name [Axis] Counterparty Name [Axis] November 15, 2032 – November 15, 2043 Debt Instrument Redemption Period Twenty Three [Member] Debt Instrument Redemption Period Twenty Three Debt Securities, First Lien 10 Debt Securities, First Lien10 [Member] Debt Securities, First Lien10 Non-PEO NEO Average Compensation Actually Paid Amount Non-PEO NEO Average Compensation Actually Paid Amount Nationwide Loan Company LLC Nationwide Loan Company LLC [Member] Nationwide Loan Company LLC Reimbursements Reimbursements [Member] Reimbursements Supplemental Disclosures Supplemental Cash Flow Information [Abstract] Reclassification adjustments included in interest expense Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax PEO Name PEO Name Preferred Stock Issued (in shares) Temporary Equity, Shares Issued SportCo Holdings, Inc. SportCo Holdings, Inc. [Member] SportCo Holdings, Inc. Other Comprehensive Income (Loss): Investment Company, Other Comprehensive Income (Loss) [Abstract] Investment Company, Other Comprehensive Income (Loss) Stock Price or TSR Estimation Method Stock Price or TSR Estimation Method [Text Block] Entity Tax Identification Number Series AA1, Series MM1, Series AA2, and Series MM2 Series AA1 and Series MM1, Series AA2, and Series MM2 [Member] Series AA1 and Series MM1, Series AA2, and Series MM2 Gains (losses) on derivative instruments designated as cash flow hedges Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax O 2027 M3 Dividends O 2027 M3 Dividends [Member] O 2027 M3 Dividends Preferred Stock dividends Preferred Stock Dividends, Income Statement Impact Due to Prospect Capital Management (Note 13) Management Fee Payable Entity Incorporation, State or Country Code Aggregate Erroneous Compensation Not Yet Determined Aggregate Erroneous Compensation Not Yet Determined [Text Block] Incentive rate Management and Service Fees, Incentive Rate Net Amount Derivative Liability, Subject to Master Netting Arrangement, after Offset and Deduction Material Terms of Trading Arrangement Material Terms of Trading Arrangement [Text Block] Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year [Member] Organization Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Software Software Sector [Member] Software Sector Debt Instrument [Axis] Subsequent Event [Table] Subsequent Event [Table] Vessel Company, LLC Vessel Company, LLC [Member] Vessel Company, LLC Capital gain Investment Company, Distribution, Long-Term Capital Gain WatchGuard Technologies, Inc. WatchGuard Technologies, Inc. [Member] WatchGuard Technologies, Inc. Julie Lindsey, Inc. Julie Lindsey, Inc. [Member] Julie Lindsey, Inc. Conversion of preferred stock to common stock (in shares) Stock Issued During Period, Shares, Conversion of Convertible Securities Related party transaction, amounts of transaction Related Party Transaction, Amounts of Transaction Basic (in dollars per share) Earnings (loss) per share - basic (in dollars per share) Earnings Per Share, Basic Remaining ownership interest Limited Liability Company or Limited Partnership, Members or Limited Partners, Remaining Ownership Interest Limited Liability Company or Limited Partnership, Members or Limited Partners, Remaining Ownership Interest Measurement Input Type [Axis] Measurement Input Type [Axis] Accretion of preferred stock to redemption value Temporary Equity, Accretion to Redemption Value Increase (decrease) in due to Prospect Administration Increase (Decrease) in Due to Related Parties Insider Trading Arrangements [Line Items] Financing costs paid and deferred Payments of Financing Costs Income Taxes [Table] Income Taxes [Table] Income Taxes [Table] Filing Two Filing Two [Member] Filing Two Dividends and Distributions to Common Shareholders Dividends and Distributions to Common Shareholders Policy [Policy Text Block] Dividends and Distributions to Common Shareholders Policy Decrease to Subordinated Structured Notes cost, net Fair Value, Measurement With Unobservable Inputs Reconciliation, Recurring Basis, Asset, Decrease to Subordinated Structured Notes Cost, Net Fair Value, Measurement With Unobservable Inputs Reconciliation, Recurring Basis, Asset, Decrease to Subordinated Structured Notes Cost, Net Debt Securities, First Lien 8 Debt Securities, First Lien8 [Member] Debt Securities, First Lien8 Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table [Member] Real Estate, Type of Property [Axis] Real Estate, Type of Property [Axis] First Lien Term Loan First Lien Term Loan [Member] First Lien Term Loan All Other Industries All Other Industry Sectors [Member] All Other Industry Sectors Financial commitment, future amount Investment Company, Financial Support to Investee Contractually Required, Not Provided, Amount Schedule of Other Income Other Income [Table Text Block] Other Income Compensation Actually Paid vs. Company Selected Measure Compensation Actually Paid vs. Company Selected Measure [Text Block] Reclassifications Reclassification, Comparability Adjustment [Policy Text Block] Debt Securities, First Lien 2 Debt Securities, First Lien2 [Member] Debt Securities, First Lien2 Fair Value Measurement Inputs and Valuation Techniques [Table] Fair Value Measurement Inputs and Valuation Techniques [Table] NMMB Holdings, Inc. NMMB Holdings, Inc. [Member] NMMB Holdings, Inc. % of Portfolio Percentage of total assets at fair value Concentration Risk, Percentage Return of capital to common stockholders Return of capital Investment Company, Tax Return of Capital Distribution Equity Awards Adjustments Equity Awards Adjustments [Member] Hedging Relationship [Domain] Hedging Relationship [Domain] Debt Securities, First Lien 9 Debt Securities, First Lien9 [Member] Debt Securities, First Lien9 Consolidated revenue interest threshold for 12 month period Consolidated Revenue Interest Threshold for 12 Month Period Consolidated Revenue Interest Threshold for 12 Month Period Debt repayments and considerations from sales of equity securities Investments Owned, At Cost, Gross Reductions Investments Owned, At Cost, Gross Reductions Industry Sector [Domain] Industry Sector [Domain] Proceeds from issuance of preferred stock Proceeds from Issuance of Preferred Stock and Preference Stock Increase (decrease) in other liabilities Increase (Decrease) in Other Operating Liabilities % of Net Assets Investment Owned, Net Assets, Percentage Series A3 6.50% Series A3 Preferred Stock [Member] 6.50% Series A3 Preferred Stock Public Notes Prospect Capital InterNotes® Long-Term Debt [Text Block] Rising Tide Holdings, Inc. Rising Tide Holdings, Inc. [Member] Rising Tide Holdings, Inc. Japs-Olson Company, LLC Japs-Olson Company, LLC [Member] Japs-Olson Company, LLC Construction & Engineering Construction & Engineering Sector [Member] Construction & Engineering Sector Galaxy XXVII CLO, Ltd. Galaxy XXVII CLO, Ltd. [Member] Galaxy XXVII CLO, Ltd. Debt Securities, First Lien 3 Debt Securities, First Lien3 [Member] Debt Securities, First Lien3 Conversion of preferred stock to common stock Stock Issued During Period, Value, Conversion of Convertible Securities Borda Canada Borda Canada [Member] Borda Canada Non-Cash Financing Activities Noncash Financing Items [Abstract] Noncash Financing Items Preferred stock, shares authorized (in shares) Preferred Stock, Shares Authorized Total distributions (in dollars per share) Investment Company, Distribution to Shareholders, Per Share Earnings multiple Measurement Input, Earnings Multiple [Member] Measurement Input, Earnings Multiple Debt Securities, First Lien 7 Debt Securities, First Lien7 [Member] Debt Securities, First Lien7 Eze Castle Integration, Inc. Eze Castle Integration, Inc. [Member] Eze Castle Integration, Inc. R-V Industries, Inc. R-V Industries, Inc. [Member] R-V Industries, Inc. Number of real estate properties Number of Real Estate Properties Takeout Fair Value Measurement Input, Takeout Fair Value [Member] Measurement Input, Takeout Fair Value Total increase (decrease) (in shares) Temporary Equity, Carrying Amount, Period Increase (Decrease), Shares Temporary Equity, Carrying Amount, Period Increase (Decrease), Shares Hedging Designation [Domain] Hedging Designation [Domain] Class of Stock [Domain] Class of Stock [Domain] Leisure Products Leisure Products Sector [Member] Leisure Products Sector Statement of Cash Flows [Abstract] Debt Securities, First Lien 4 Debt Securities, First Lien4 [Member] Debt Securities, First Lien4 Foreign Exchange Forward Foreign Exchange Forward [Member] TP Pueblo, LLC TP Pueblo, LLC [Member] TP Pueblo, LLC Series M5 Series M5 7.50% Series M5 Preferred Stock [Member] 7.50% Series M5 Preferred Stock Schedule of Stock by Class Schedule of Stock by Class [Table Text Block] Payment-In-Kind interest and dividend income Interest Income, Operating And Non-Cash, Paid in Kind And Dividend Income Interest Income, Operating And Non-Cash, Paid in Kind And Dividend Income Aggregate Available Trading Arrangement, Securities Aggregate Available Amount Investment Classification, Transactions and Risks Investment, Policy [Policy Text Block] Common stock, consecutive trading days, volume weighted average price Common Stock, Consecutive Trading Days, Volume Weighted Average Price Common Stock, Consecutive Trading Days, Volume Weighted Average Price Net change in unrealized gains (losses) from derivative instruments and foreign currency transactions Unrealized Gain (Loss), Foreign Currency Transaction And Derivatives, after Tax Unrealized Gain (Loss), Foreign Currency Transaction And Derivatives, after Tax 2017 Notes 2017 Notes [Member] 2017 Notes Income Taxes Income Tax Disclosure [Text Block] First Lien Debt Debt Securities, First Lien [Member] Debt Securities, First Lien Redemptions/Repurchases (in shares) Temporary Equity, Shares, Converted To Common and Repurchased Temporary Equity, Shares, Converted To Common and Repurchased Time dividends have remained unpaid Unpaid Dividends, Preferred Stock, Term Unpaid Dividends, Preferred Stock, Term Annualized floating rate Annualized Floating Rate Annualized Floating Rate Pay vs Performance Disclosure Pay vs Performance Disclosure [Table] Investment Company, Financial Highlights [Table] Investment Company, Financial Highlights [Table] Spectrum Vision Holdings, LLC Spectrum Vision Holdings, LLC [Member] Spectrum Vision Holdings, LLC Series A4 6.50% Series A4 Preferred Stock [Member] 6.50% Series A4 Preferred Stock Entity Filer Category Equity rates of return Measurement Input, Equity Rates Of Return [Member] Measurement Input, Equity Rates Of Return Dividends [Axis] Dividends [Axis] Revision of Prior Period [Axis] Revision of Prior Period [Axis] Schedule of Offsetting Liabilities Offsetting Liabilities [Table Text Block] Series M4 6.50% Series M4 Preferred Stock [Member] 6.50% Series M4 Preferred Stock Average stated interest rate Debt Instrument, Interest Rate During Period Gain (loss) on Accretion to Redemption Value of Preferred Stock Gain (Loss) on Accretion to Redemption Value of Preferred Stock Gain (Loss) on Accretion to Redemption Value of Preferred Stock Financing Receivable Name [Axis] Financing Receivable Name [Axis] Financing Receivable Name Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] BFC-SDR, LLC BFC-SDR, LLC [Member] BFC-SDR, LLC Net change in unrealized (losses) gains on investments still held Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss) Schedule of Stock by Class [Table] Stock, Class of Stock [Table] Student Housing Student Housing [Member] Student Housing Total Investment Income Total income Gross Investment Income, Operating Maximum Offering Size (Shares) Temporary Equity, Maximum Offering Size Temporary Equity, Maximum Offering Size Derivative Liability Fair Value Foreign currency forward contracts - Liabilities Gross Fair Value Amount of Recognized Liabilities Derivative Liability 5.50% Preferred Stock, 6.50% Preferred Stock 5.50% Preferred Stock, 6.50% Preferred Stock [Member] 5.50% Preferred Stock, 6.50% Preferred Stock Senior Notes Senior Notes [Member] Foreign Currency Foreign Currency Transactions and Translations Policy [Policy Text Block] Entity Address, Address Line One Number of assets transferred out of Level 2 to Level 3 Number of Assets Transferred Out Of Level 2 To Level 3 Number of Assets Transferred Out Of Level 2 To Level 3 Credit Facility, Usage [Domain] Credit Facility, Usage [Domain] Credit Facility, Usage [Domain] Electrical Equipment Electrical Equipment [Member] Electrical Equipment June 15, 2027 – November 15, 2029 Debt Instrument Redemption Period Sixteen [Member] Debt Instrument Redemption Period Sixteen Forward Contracts designated as fair value hedging instruments Fair Value Hedging [Member] O 2027 M2 Dividends O 2027 M2 Dividends [Member] O 2027 M2 Dividends Investments in and Advances to Affiliates, at Fair Value [Roll Forward] Investments in and Advances to Affiliates, at Fair Value [Roll Forward] 2026 Notes 2026 Notes [Member] 2026 Notes Consolidation Consolidation, Policy [Policy Text Block] Portfolio turnover rate Investment Company, Portfolio Turnover Real Estate Management & Development Real Estate Management & Development Sector [Member] Real Estate Management & Development Sector First Lien, Unitranche Debt Securities, First Lien, Unitranche [Member] Debt Securities, First Lien, Unitranche Net realized and unrealized (losses) gains Fair Value, Measurement With Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Fair Value, Measurement With Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) CP Well CP Well [Member] CP Well Wolf Energy Holdings, Inc. Wolf Energy Holdings, Inc. [Member] Wolf Energy Holdings, Inc. Proceeds from legal settlements Proceeds from Legal Settlements Calculated interest basis, number of months Calculated Interest Basis, Number of Months Calculated Interest Basis, Number of Months Discounted cash flow (Yield analysis) Valuation Technique, Discounted Cash Flow [Member] Repayment of Loan Receivable Repayment of loan receivable Proceeds from Collection of Loans Receivable Statement [Table] Statement [Table] Return of Capital to common stockholders (in dollars per share) Investment Company, Return of Capital, Per Share Investment Company, Return of Capital, Per Share Converted to equity Debt Conversion, Converted Instrument, Amount Debt Securities, First Lien 6 Debt Securities, First Lien6 [Member] Debt Securities, First Lien6 Net increase (decrease) from operations applicable to common stockholders (in dollars per share) Investment Company, Investment Income (Loss) from Operations Net of Distributions to Preferred Stockholders, Per Share Investment Company, Investment Income (Loss) from Operations Net of Distributions to Preferred Stockholders, Per Share Gross Amounts of Recognized Assets (Liabilities) Derivative Asset, Subject to Master Netting Arrangement, before Offset Victor Holdings of Delaware, LLC Victor Holdings of Delaware, LLC [Member] Victor Holdings of Delaware, LLC Emerge Intermediate, Inc Emerge Intermediate, Inc [Member] Emerge Intermediate, Inc November 15, 2038 – May 15, 2039 Debt Instrument Redemption Period Twenty Four [Member] Debt Instrument Redemption Period Twenty Four AerLift Leasing Limited AerLift Leasing Limited [Member] AerLift Leasing Limited Strategic Chemical Solutions Corp. (f/k/a USES Corp.) Strategic Chemical Solutions Corp Strategic Chemical Solutions Corp [Member] Strategic Chemical Solutions Corp First Lien Note First Lien Note [Member] First Lien Note Tenor at Origination (in years) Long-Term Debt, Term Derivative Instruments and Hedging Activities Disclosure [Abstract]