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INVESTMENTS - Narrative (Details) $ in Thousands | 1 Months Ended | 3 Months Ended | 12 Months Ended
--- | --- | --- | ---
Dec. 31, 2023 USD ($) industry portfolioCompany investment state | Nov. 30, 2023 USD ($) | Oct. 30, 2022 USD ($) | Dec. 31, 2023 USD ($) industry portfolioCompany investment state | Dec. 31, 2022 USD ($) | Sep. 30, 2023 USD ($) investment
Summary of Investment Holdings [Line Items] |  |  |  |  |  |  |
Number of proprietary investments | investment | 47 |  |  | 47 |  |  |
Fair Value | $ 749,985 |  |  | $ 749,985 |  | $ 704,815 | [1]
Purchase of investments |  |  |  | 57,998 | $ 13,379 |  |
Investment company, committed capital |  |  |  | $ 54,710 |  | 45,231 |
Number of investment portfolio company | portfolioCompany | 51 |  |  | 51 |  |  |
Number of states which have invested in the company location | state | 24 |  |  | 24 |  |  |
Number of industries that have made investments | industry | 12 |  |  | 12 |  |  |
Weighted average investment owned, at cost, amount | $ 14,900 |  |  | $ 14,900 |  | 14,200 |
Debt investments with maturity dates prior to period end | 200 |  |  | 200 |  |  |
Gross receivables from portfolio companies | 900 |  |  | 900 |  | 800 |
Allowance for uncollectible receivables | 14 |  |  | 14 |  | 9 |
Targus Cayman HoldCo Ltd. |  |  |  |  |  |  |
Summary of Investment Holdings [Line Items] |  |  |  |  |  |  |
Net proceeds from the sale of investments |  |  | $ 8,000 |  |  |  |
Realized investment gains |  |  | $ 5,900 |  |  |  |
Environmental Midco, Inc |  |  |  |  |  |  |
Summary of Investment Holdings [Line Items] |  |  |  |  |  |  |
Purchase of investments |  | $ 11,000 |  |  |  |  |
Investment company, committed capital |  | 2,000 |  |  |  |  |
Salt & Straw, LLC |  |  |  |  |  |  |
Summary of Investment Holdings [Line Items] |  |  |  |  |  |  |
Purchase of investments | 7,000 |  |  |  |  |  |
Investment company, delayed draw term loan commitment | 2,900 |  |  |  |  |  |
Leadpoint Business Services, LLC, |  |  |  |  |  |  |
Summary of Investment Holdings [Line Items] |  |  |  |  |  |  |
Purchase of investments | 12,000 |  |  |  |  |  |
ALS Education, LLC |  |  |  |  |  |  |
Summary of Investment Holdings [Line Items] |  |  |  |  |  |  |
Purchase of investments | 14,300 |  |  |  |  |  |
Cafe Zupas |  |  |  |  |  |  |
Summary of Investment Holdings [Line Items] |  |  |  |  |  |  |
Investment company, committed capital |  | 10,500 |  |  |  |  |
Investment company, delayed draw term loan commitment |  | 1,400 |  |  |  |  |
Net proceeds from the sale of investments |  | 7,300 |  |  |  |  |
PIC 360 |  |  |  |  |  |  |
Summary of Investment Holdings [Line Items] |  |  |  |  |  |  |
Realized investment gains |  | $ 300 |  |  |  |  |
Principal or Proprietary Transactions |  |  |  |  |  |  |
Summary of Investment Holdings [Line Items] |  |  |  |  |  |  |
Fair Value | $ 739,900 |  |  | $ 739,900 |  | $ 695,100 |
Syndicated Investments |  |  |  |  |  |  |
Summary of Investment Holdings [Line Items] |  |  |  |  |  |  |
Number of proprietary investments | investment | 4 |  |  | 4 |  | 4 |
Fair Value | $ 10,100 |  |  | $ 10,100 |  | $ 9,700 |
Investment Portfolio Benchmark | Investment Type Concentration Risk | Principal or Proprietary Transactions |  |  |  |  |  |  |
Summary of Investment Holdings [Line Items] |  |  |  |  |  |  |
Concentration risk, percentage |  |  |  | 98.70% |  | 98.60% |
Investment Portfolio Benchmark | Investment Type Concentration Risk | Syndicated Investments |  |  |  |  |  |  |
Summary of Investment Holdings [Line Items] |  |  |  |  |  |  |
Concentration risk, percentage |  |  |  | 1.30% |  | 1.40% |
Investment Portfolio Benchmark | Customer Concentration Risk | Five Largest Portfolio Investments |  |  |  |  |  |  |
Summary of Investment Holdings [Line Items] |  |  |  |  |  |  |
Fair Value | $ 185,700 |  |  | $ 185,700 |  | $ 176,900 |
Concentration risk, percentage |  |  |  | 24.80% |  | 25.10% |
[1] | Investment was exited subsequent to December 31, 2023. Refer to Note 12 – Subsequent Events in the accompanying Notes to the Consolidated Financial Statements for additional information.

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