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Summary of Significant Accounting Policies - Additional Information (Details) | 3 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Mar. 31, 2024 USD ($) Loan Equipment | Mar. 31, 2023 USD ($) | Dec. 31, 2023 USD ($) Equipment Loan | Dec. 31, 2022 USD ($)
Disclosure Of Summary Of Significant Accounting Policies [Line Items] |  |  |  |
Fair value of companies investment percentage | 98.60% |  |  |
Market index of investment securities | $ 0 |  |  |
Maturity period description | original maturity of three months or less |  |  |
Cash and cash equivalents | $ 11,967,000 |  | $ 4,761,000 |
Total cash, cash equivalents and restricted cash shown in the Consolidated Statements of Cash Flows | $ 11,967,000 | $ 8,344,000 | 4,761,000 | $ 10,612,000
Escrow Distribution period | 1 year |  |  |
Escrow receivable balance | $ 2,400,000 |  | $ 2,400,000 |
Interest income | 4,100,000 | 300,000 |  |
Dividend income | $ 200,000 | $ 0 |  |
Debt security payment due | 90 days |  |  |
Number of portfolio companies loans | Loan | 4 |  | 3 |
Number of portfolio companies equipment financing | Equipment | 1 |  | 2 |
Non accrual cost | $ 67,500,000 |  | $ 60,800,000 |
Fair value | $ 30,400,000 |  | $ 43,200,000 |
Fair value of debt investment portfolio | 2.40% |  | 3.50% |
Debt instrument percentage | 6.00% |  |  |
Investment percentage | 16.30% | 16.90% |  |
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 | $ 4,900,000 |  | $ 3,100,000 |
Minimum |  |  |  |
Disclosure Of Summary Of Significant Accounting Policies [Line Items] |  |  |  |
Investment percentage | 90.00% |  |  |

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