v3.23.3

Taxable/Distributable Income and Dividend Distributions - Narrative (Details) - USD ($) $ in Thousands | 12 Months Ended
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Sep. 30, 2023 | Sep. 30, 2022 | Sep. 30, 2021
Investments, Owned, Federal Income Tax Note [Line Items] |  |  |
Undistributed ordinary income, net | $ 558,300 |  |
Valuation allowance | 8,100 |  |
Deferred tax assets | 8,100 |  |
(Provision) benefit for taxes on realized and unrealized gains (losses) | 1,656 | $ 329 | $ 785
Income tax expense (benefit) |  | 1,300 | 700
Deferred taxes | 1,670 | (973) | 133
(Provision) benefit for taxes on net investment income | 0 | $ 3,308 | $ 2,795
Cost of investments | 3,070,000 |  |
Unrealized appreciation | 529,500 |  |
Unrealized depreciation | 704,500 |  |
Unrealized appreciation (depreciation) | 175,000 |  |
Short-Term Capital Loss Carryforward |  |  |
Investments, Owned, Federal Income Tax Note [Line Items] |  |  |
Undistributed ordinary income, net | 70,300 |  |
Long-Term Capital Loss Carryforward |  |  |
Investments, Owned, Federal Income Tax Note [Line Items] |  |  |
Undistributed ordinary income, net | $ 488,000 |  |

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