Consolidated Statements of Assets and Liabilities (Parenthetical) - USD ($) $ in Thousands |
Jun. 30, 2026 |
Sep. 30, 2025 |
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|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Investments at cost | $ 2,627,447 | [1],[2] | $ 2,819,393 | [3],[4],[5],[6] | ||||||||||||||||||
| Cash at cost | 50,090 | [7],[8],[9] | 81,955 | [5],[6] | ||||||||||||||||||
| Cash and cash equivalents at cost | 50,725 | 40,729 | ||||||||||||||||||||
| Credit facility payable, cost | $ 318,355 | $ 683,855 | ||||||||||||||||||||
| Common stock, shares, issued | 99,217,896 | 99,217,896 | ||||||||||||||||||||
| Common stock, shares, outstanding | 99,217,896 | 99,217,896 | ||||||||||||||||||||
| Common stock par value | $ 0.001 | $ 0.001 | ||||||||||||||||||||
| Common stock, shares authorized | 200,000,000 | 200,000,000 | ||||||||||||||||||||
| 2036 Asset-Backed Debt | ||||||||||||||||||||||
| Asset-backed debt payable, net | $ 0 | $ 287,000 | ||||||||||||||||||||
| Unamortized deferred financing costs | 0 | 2,373 | ||||||||||||||||||||
| 2036-R Asset-Backed Debt | ||||||||||||||||||||||
| Asset-backed debt payable, net | 287,000 | 266,000 | ||||||||||||||||||||
| Unamortized deferred financing costs | 391 | 634 | ||||||||||||||||||||
| 2037 Asset-Backed Debt | ||||||||||||||||||||||
| Asset-backed debt payable, net | 389,500 | 361,000 | ||||||||||||||||||||
| Unamortized deferred financing costs | 2,234 | 2,669 | ||||||||||||||||||||
| 2038-R Asset-Backed Debt | ||||||||||||||||||||||
| Asset-backed debt payable, net | 287,000 | 0 | ||||||||||||||||||||
| Unamortized deferred financing costs | 2,135 | 0 | ||||||||||||||||||||
| 2026 Notes Payable | ||||||||||||||||||||||
| Notes payable, par | 0 | 185,000 | ||||||||||||||||||||
| Unamortized deferred financing costs | 0 | 391 | ||||||||||||||||||||
| 2029 Notes Payable | ||||||||||||||||||||||
| Notes payable, par | 200,000 | 0 | ||||||||||||||||||||
| Unamortized deferred financing costs | 3,788 | 0 | ||||||||||||||||||||
| 2031 Notes Payable | ||||||||||||||||||||||
| Notes payable, par | 105,000 | 0 | ||||||||||||||||||||
| Unamortized deferred financing costs | 3,745 | 0 | ||||||||||||||||||||
| Non-controlled, Non-affiliated Investments | ||||||||||||||||||||||
| Investments at cost | 2,132,947 | 2,458,018 | ||||||||||||||||||||
| Controlled, affiliated investments | ||||||||||||||||||||||
| Investments at cost | $ 494,500 | $ 361,375 | ||||||||||||||||||||
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