v3.26.1
Financial Highlights (Details) - USD ($)
$ / shares in Units, shares in Thousands, $ in Thousands
 3 Months Ended 9 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Investment Company, Financial Highlights [Roll Forward]        
Net asset value per share at beginning of period (in dollars per share) $ 15.69 $ 16.75 $ 16.64 $ 18.09
Net investment income (in dollars per share) 0.37 0.38 1.18 1.37
Net unrealized appreciation (depreciation) (in dollars per share) 0.54 0.20 (0.28) (0.98)
Net realized gains (losses) (in dollars per share) (0.56) (0.15) (0.70) (0.28)
Distributions of net investment income to stockholders (dollars per share) (0.34) (0.42) (1.14) (1.44)
Net asset value per share at end of period (in dollars per share) 15.70 16.76 15.70 16.76
Per share market value at beginning of period (in dollars per share) 11.30 15.36 13.05 16.31
Per share market value at end of period (in dollars per share) $ 11.94 $ 13.66 $ 11.94 $ 13.66
Total return 8.60% (8.39%) 0.33% (7.93%)
Common shares outstanding at beginning of period (in shares) 88,086 88,086 88,086 82,245
Common shares outstanding at end of period (in shares) 88,086 88,086 88,086 88,086
Net assets at beginning of period $ 1,382,064 $ 1,475,113 $ 1,465,813 $ 1,487,811
Net assets at end of period 1,383,055 1,476,469 1,383,055 1,476,469
Average net assets $ 1,392,778 $ 1,488,823 $ 1,425,294 $ 1,487,303
Ratio of net investment income to average net assets 9.37% 9.02% 9.72% 10.50%
Ratio of total expenses to average net assets 10.54% 12.69% 10.41% 12.72%
Ratio of net expenses to average net assets 10.54% 11.24% 10.41% 10.97%
Ratio of portfolio turnover to average investments at fair value 8.50% 4.86% 26.32% 25.59%
Weighted average outstanding debt $ 1,496,549 $ 1,477,143 $ 1,554,271 $ 1,595,421
Average debt per share (dollars per share) $ 16.99 $ 16.77 $ 17.65 $ 18.68
Asset coverage ratio 194.16% 199.86% 194.16% 199.86%
Outstanding senior securities $ 1,454,700 $ 1,466,100 $ 1,454,700 $ 1,466,100