Annual report [Section 13 and 15(d), not S-K Item 405]

INVESTMENTS - Schedule of Investment Holdings (Details)

v3.25.3
INVESTMENTS - Schedule of Investment Holdings (Details) - USD ($)
$ in Thousands
 12 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Summary of Investment Holdings [Line Items]    
Cost $ 876,614 [1] $ 771,011 [2]
Fair Value 859,124 [1] 796,260 [2]
South    
Summary of Investment Holdings [Line Items]    
Fair Value 287,371 314,010
Midwest    
Summary of Investment Holdings [Line Items]    
Fair Value 237,417 192,897
West    
Summary of Investment Holdings [Line Items]    
Fair Value 233,564 249,082
Northeast    
Summary of Investment Holdings [Line Items]    
Fair Value 100,772 40,271
Healthcare, Education, and Childcare    
Summary of Investment Holdings [Line Items]    
Fair Value 273,262 101,707
Diversified/Conglomerate Manufacturing    
Summary of Investment Holdings [Line Items]    
Fair Value 202,466 160,264
Diversified/Conglomerate Service    
Summary of Investment Holdings [Line Items]    
Fair Value 152,042 179,032
Beverage, Food, and Tobacco    
Summary of Investment Holdings [Line Items]    
Fair Value 54,605 88,327
Home and Office Furnishings, Housewares and Durable Consumer Products    
Summary of Investment Holdings [Line Items]    
Fair Value 30,000 0
Automobile    
Summary of Investment Holdings [Line Items]    
Fair Value 27,361 28,286
Machinery    
Summary of Investment Holdings [Line Items]    
Fair Value 26,381 21,816
Personal, Food, and Miscellaneous Services    
Summary of Investment Holdings [Line Items]    
Fair Value 23,700 0
Cargo Transportation    
Summary of Investment Holdings [Line Items]    
Fair Value 20,000 20,200
Oil and Gas    
Summary of Investment Holdings [Line Items]    
Fair Value 17,512 20,554
Personal and Non-Durable Consumer Products    
Summary of Investment Holdings [Line Items]    
Fair Value 13,866 13,586
Printing and Publishing    
Summary of Investment Holdings [Line Items]    
Fair Value 5,809 4,312
Aerospace and Defense    
Summary of Investment Holdings [Line Items]    
Fair Value 1,184 153,096
Other    
Summary of Investment Holdings [Line Items]    
Fair Value $ 10,936 $ 5,080
Investment Owned, At Cost | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 100.00% 100.00%
Investment Owned, At Fair Value | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 100.00% 100.00%
Investment Owned, At Fair Value | Industry Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 100.00% 100.00%
Investment Owned, At Fair Value | Industry Concentration Risk | Healthcare, Education, and Childcare    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 31.80% 12.80%
Investment Owned, At Fair Value | Industry Concentration Risk | Diversified/Conglomerate Manufacturing    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 23.60% 20.10%
Investment Owned, At Fair Value | Industry Concentration Risk | Diversified/Conglomerate Service    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 17.70% 22.50%
Investment Owned, At Fair Value | Industry Concentration Risk | Beverage, Food, and Tobacco    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 6.40% 11.10%
Investment Owned, At Fair Value | Industry Concentration Risk | Home and Office Furnishings, Housewares and Durable Consumer Products    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 3.50% 0.00%
Investment Owned, At Fair Value | Industry Concentration Risk | Automobile    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 3.20% 3.60%
Investment Owned, At Fair Value | Industry Concentration Risk | Machinery    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 3.10% 2.70%
Investment Owned, At Fair Value | Industry Concentration Risk | Personal, Food, and Miscellaneous Services    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 2.70% 0.00%
Investment Owned, At Fair Value | Industry Concentration Risk | Cargo Transportation    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 2.30% 2.50%
Investment Owned, At Fair Value | Industry Concentration Risk | Oil and Gas    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 2.00% 2.60%
Investment Owned, At Fair Value | Industry Concentration Risk | Personal and Non-Durable Consumer Products    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 1.60% 1.70%
Investment Owned, At Fair Value | Industry Concentration Risk | Printing and Publishing    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 0.70% 0.50%
Investment Owned, At Fair Value | Industry Concentration Risk | Aerospace and Defense    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 0.10% 19.20%
Investment Owned, At Fair Value | Industry Concentration Risk | Other    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 1.30% 0.70%
Investment Owned, At Fair Value | Geographic Regions Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 100.00% 100.00%
Investment Owned, At Fair Value | Geographic Regions Risk | South    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 33.50% 39.40%
Investment Owned, At Fair Value | Geographic Regions Risk | Midwest    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 27.60% 24.20%
Investment Owned, At Fair Value | Geographic Regions Risk | West    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 27.20% 31.30%
Investment Owned, At Fair Value | Geographic Regions Risk | Northeast    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 11.70% 5.10%
Debt Securities    
Summary of Investment Holdings [Line Items]    
Cost $ 796,623 $ 694,625
Fair Value $ 773,246 $ 668,685
Debt Securities | Investment Owned, At Cost | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 90.90% 90.10%
Debt Securities | Investment Owned, At Fair Value | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 90.00% 84.00%
Secured first lien debt    
Summary of Investment Holdings [Line Items]    
Cost $ 646,131 $ 580,736
Fair Value $ 622,371 $ 554,937
Secured first lien debt | Investment Owned, At Cost | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 73.70% 75.30%
Secured first lien debt | Investment Owned, At Fair Value | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 72.40% 69.70%
Secured second lien debt    
Summary of Investment Holdings [Line Items]    
Cost $ 149,937 $ 113,691
Fair Value $ 150,542 $ 113,716
Secured second lien debt | Investment Owned, At Cost | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 17.10% 14.80%
Secured second lien debt | Investment Owned, At Fair Value | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 17.50% 14.30%
Unsecured debt    
Summary of Investment Holdings [Line Items]    
Cost $ 555 $ 198
Fair Value $ 333 $ 32
Unsecured debt | Investment Owned, At Cost | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 0.10% 0.00%
Unsecured debt | Investment Owned, At Fair Value | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 0.10% 0.00%
Equity Securities    
Summary of Investment Holdings [Line Items]    
Cost $ 79,991 $ 76,386
Fair Value $ 85,878 $ 127,575
Equity Securities | Investment Owned, At Cost | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 9.10% 9.90%
Equity Securities | Investment Owned, At Fair Value | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 10.00% 16.00%
Preferred equity    
Summary of Investment Holdings [Line Items]    
Cost $ 37,429 $ 45,017
Fair Value $ 31,214 $ 31,346
Preferred equity | Investment Owned, At Cost | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 4.30% 5.80%
Preferred equity | Investment Owned, At Fair Value | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 3.60% 3.90%
Common equity/equivalents    
Summary of Investment Holdings [Line Items]    
Cost $ 42,562 $ 31,369
Fair Value $ 54,664 $ 96,229
Common equity/equivalents | Investment Owned, At Cost | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 4.80% 4.10%
Common equity/equivalents | Investment Owned, At Fair Value | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 6.40% 12.10%
[1] Cumulative gross unrealized depreciation for federal income tax purposes is $59.7 million; cumulative gross unrealized appreciation for federal income tax purposes is $34.1 million. Cumulative net unrealized depreciation is $25.5 million, based on a tax cost of $884.7 million.
[2] Cumulative gross unrealized depreciation for federal income tax purposes is $66.1 million; cumulative gross unrealized appreciation for federal income tax purposes is $85.8 million. Cumulative net unrealized appreciation is $19.7 million, based on a tax cost of $776.5 million