Taxes and Distributions - Summary of Reconciles Net (Decrease) Increase in Net Assets Resulting From Operations to Taxable Income (Details) - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Sep. 30, 2025 |
Sep. 30, 2024 |
Sep. 30, 2023 |
|
| Income Tax Disclosure [Abstract] | |||
| Net increase (decrease) in net assets resulting from operations | $ 32,725 | $ 48,852 | $ (33,807) |
| Net realized (gain) loss on investments | 52,434 | 33,646 | 156,757 |
| Net change in unrealized (appreciation) depreciation on investments and debt | (39,108) | (22,428) | (57,417) |
| Other book-to-tax differences | (1,551) | 9,268 | (6,006) |
| Other non-deductible expenses | 3,372 | 3,245 | 5,766 |
| Taxable income before dividends paid deduction | $ 47,872 | $ 72,583 | $ 65,293 |