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Summary of Significant Accounting Policies - Additional Information (Details) | 12 Months Ended
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Dec. 31, 2024 USD ($) Loan Equipment | Dec. 31, 2023 USD ($) Loan | Dec. 31, 2022 USD ($) | Dec. 31, 2021 USD ($) | Dec. 31, 2020
Disclosure Of Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |
Fair value of companies investment percentage | 99.10% |  |  |  |
Market index of investment securities | $ 0 |  |  |  |
Maturity period description | original maturity of three months or less |  |  |  |
Total cash, cash equivalents and restricted cash shown in the Consolidated Statements of Cash Flows | $ 9,627,000 | $ 4,761,000 | $ 10,612,000 | $ 46,742,000 |
Cash and cash equivalents | 9,627,000 | 4,761,000 | 10,612,000 |  |
Restricted cash | $ 0 | 0 |  |  |
Escrow Distribution period | 1 year |  |  |  |
Escrow receivables balance | $ 0 | 2,400,000 |  |  |
Interest income | 9,100,000 | 8,000,000 | 300,000 |  |
Dividend income | $ 1,600,000 | $ 600,000 | $ 0 |  |
Debt security payment due | 90 days |  |  |  |
Number of portfolio companies loans | Loan | 3 | 3 |  |  |
Number of portfolio companies equipment financing | Equipment | 2 |  |  |  |
Non accrual cost | $ 43,300,000 | $ 60,800,000 |  |  |
Fair value | $ 12,700,000 | $ 43,200,000 |  |  |
Fair value of debt investment portfolio | 0.80% | 3.50% |  |  |
Debt instrument percentage | 6.00% |  |  |  |
Investment percentage | 16.70% | 17.50% | 15.70% | 10.50% | 10.50%
Percentage of net tax- exempt income | 90.00% |  |  |  |
Uncertain tax position | $ 0 | $ 0 |  |  |
Nondeductible federal excise tax | 4.00% |  |  |  |
Ordinary income percentage | 98.00% |  |  |  |
Capital gain net income percentage | 98.20% |  |  |  |
Excise tax | 4.00% |  |  |  |
Goldman Sachs Financial Square Government Institutional Fund |  |  |  |  |
Disclosure Of Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |
Cash and cash equivalents | $ 3,800,000 | $ 3,100,000 |  |  |
Minimum |  |  |  |  |
Disclosure Of Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |
Cash and cash equivalents interest rate | 3.00% |  |  |  |
Investment percentage | 90.00% |  |  |  |
Maximum |  |  |  |  |
Disclosure Of Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |
Cash and cash equivalents interest rate | 6.00% |  |  |  |

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