Income Taxes - Narrative (Details) - USD ($) |
12 Months Ended | 14 Months Ended | 26 Months Ended | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Aug. 26, 2025 |
Jun. 30, 2026 |
Aug. 31, 2025 |
Jun. 30, 2025 |
Aug. 31, 2024 |
Jun. 30, 2024 |
Aug. 31, 2023 |
Aug. 31, 2024 |
Aug. 31, 2025 |
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| Income Taxes [Line Items] | |||||||||||||
| Ordinary income | $ 189,162,000 | $ 227,508,000 | $ 243,085,000 | ||||||||||
| Return of capital | $ 10,394,000 | $ 10,170,000 | [1] | 69,913,000 | $ 70,137,000 | [1] | $ 71,414,000 | $ 67,479,000 | $ 44,838,000 | ||||
| Distributable loss | 1,253,880,000 | 1,387,494,000 | 1,194,137,000 | ||||||||||
| Investment company, distributable earnings (loss), accumulated ordinary income (loss) | 0 | $ 0 | |||||||||||
| Investment company, distributable earnings (loss), accumulated long-term capital gain (loss) | 0 | 0 | |||||||||||
| Investment company, distributable earnings (loss), accumulated capital loss carryforward | $ 711,167,000 | 711,167,000 | |||||||||||
| Cost basis of investments for tax purposes | 6,367,797,000 | 6,800,692,000 | |||||||||||
| Unrealized appreciation (depreciation), net | 25,239,000 | (127,176,000) | |||||||||||
| Unrealized gains | 1,263,482,000 | 1,308,011,000 | |||||||||||
| Unrealized losses | 1,288,721,000 | 1,435,187,000 | |||||||||||
| Distributions in excess of earnings | |||||||||||||
| Income Taxes [Line Items] | |||||||||||||
| Reclassification of distributions from capital, increase (decrease) | 10,170,000 | $ 63,000 | 97,000 | ||||||||||
| Accumulated Realized Losses | |||||||||||||
| Income Taxes [Line Items] | |||||||||||||
| Reclassification of distributions from capital, increase (decrease) | (21,530,000) | (16,242,000) | |||||||||||
| Paid-in capital in excess of par | |||||||||||||
| Income Taxes [Line Items] | |||||||||||||
| Return of capital | $ 10,170,000 | [1] | 70,137,000 | [1] | $ 67,479,000 | ||||||||
| Reclassification of distributions from capital, increase (decrease) | $ (21,593,000) | $ (16,339,000) | |||||||||||
| Reclassification, Adjustment | |||||||||||||
| Income Taxes [Line Items] | |||||||||||||
| Distributable loss | $ 59,743,000 | ||||||||||||
| Scenario, Plan | |||||||||||||
| Income Taxes [Line Items] | |||||||||||||
| Ordinary income | $ 360,488,000 | ||||||||||||
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