Quarterly report [Sections 13 or 15(d)]

INVESTMENTS - Schedule of Investment Concentrations (Details)

v3.26.3
INVESTMENTS - Schedule of Investment Concentrations (Details) - USD ($)
$ in Thousands
 6 Months Ended 12 Months Ended
Sep. 30, 2026
Mar. 31, 2026
Summary of Investment Holdings [Line Items]    
Cost $ 1,181,079 $ 1,052,848 [1]
Fair Value 1,430,865 1,309,248 [1]
South    
Summary of Investment Holdings [Line Items]    
Fair Value 631,988 649,436
West    
Summary of Investment Holdings [Line Items]    
Fair Value 270,226 227,294
Northeast    
Summary of Investment Holdings [Line Items]    
Fair Value 256,321 193,837
Midwest    
Summary of Investment Holdings [Line Items]    
Fair Value 240,437 216,726
Canada    
Summary of Investment Holdings [Line Items]    
Fair Value 31,893 21,955
Diversified/Conglomerate Services    
Summary of Investment Holdings [Line Items]    
Fair Value 258,676 189,148
Machinery (Non-Agriculture, Non-Construction, and Non-Electronic)    
Summary of Investment Holdings [Line Items]    
Fair Value 222,508 258,692
Aerospace and Defense    
Summary of Investment Holdings [Line Items]    
Fair Value 206,150 174,542
Home and Office Furnishings, Housewares, and Durable Consumer Products    
Summary of Investment Holdings [Line Items]    
Fair Value 175,903 166,553
Oil and Gas    
Summary of Investment Holdings [Line Items]    
Fair Value 116,883 125,605
Leisure, Amusement, Motion Pictures, and Entertainment    
Summary of Investment Holdings [Line Items]    
Fair Value 109,775 105,339
Electronics    
Summary of Investment Holdings [Line Items]    
Fair Value 68,479 62,723
Diversified/Conglomerate Manufacturing    
Summary of Investment Holdings [Line Items]    
Fair Value 65,848 6,763
Chemicals, Plastics, and Rubber    
Summary of Investment Holdings [Line Items]    
Fair Value 55,065 49,715
Buildings and Real Estate    
Summary of Investment Holdings [Line Items]    
Fair Value 51,810 68,987
Mining, Steel, Iron and Non-Precious Metals    
Summary of Investment Holdings [Line Items]    
Fair Value 44,438 37,713
Healthcare, Education, and Childcare    
Summary of Investment Holdings [Line Items]    
Fair Value 40,289 41,630
Other less than 2.0%    
Summary of Investment Holdings [Line Items]    
Fair Value $ 15,041 $ 21,838
Investment Owned, at Cost | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 100.00% 100.00%
Investment Owned, at Fair Value | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 100.00% 100.00%
Investment Owned, at Fair Value | Industry Concentration Risk    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 100.00% 100.00%
Investment Owned, at Fair Value | Industry Concentration Risk | Diversified/Conglomerate Services    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 18.10% 14.40%
Investment Owned, at Fair Value | Industry Concentration Risk | Machinery (Non-Agriculture, Non-Construction, and Non-Electronic)    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 15.60% 19.80%
Investment Owned, at Fair Value | Industry Concentration Risk | Aerospace and Defense    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 14.40% 13.40%
Investment Owned, at Fair Value | Industry Concentration Risk | Home and Office Furnishings, Housewares, and Durable Consumer Products    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 12.30% 12.70%
Investment Owned, at Fair Value | Industry Concentration Risk | Oil and Gas    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 8.20% 9.60%
Investment Owned, at Fair Value | Industry Concentration Risk | Leisure, Amusement, Motion Pictures, and Entertainment    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 7.70% 8.00%
Investment Owned, at Fair Value | Industry Concentration Risk | Electronics    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 4.80% 4.80%
Investment Owned, at Fair Value | Industry Concentration Risk | Diversified/Conglomerate Manufacturing    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 4.60% 0.50%
Investment Owned, at Fair Value | Industry Concentration Risk | Chemicals, Plastics, and Rubber    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 3.80% 3.80%
Investment Owned, at Fair Value | Industry Concentration Risk | Buildings and Real Estate    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 3.60% 5.30%
Investment Owned, at Fair Value | Industry Concentration Risk | Mining, Steel, Iron and Non-Precious Metals    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 3.10% 2.90%
Investment Owned, at Fair Value | Industry Concentration Risk | Healthcare, Education, and Childcare    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 2.80% 3.20%
Investment Owned, at Fair Value | Industry Concentration Risk | Other less than 2.0%    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 1.00% 1.60%
Investment Owned, at Fair Value | Geographic Regions Risk    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 100.00% 100.00%
Investment Owned, at Fair Value | Geographic Regions Risk | South    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 44.20% 49.60%
Investment Owned, at Fair Value | Geographic Regions Risk | West    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 18.90% 17.30%
Investment Owned, at Fair Value | Geographic Regions Risk | Northeast    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 17.90% 14.80%
Investment Owned, at Fair Value | Geographic Regions Risk | Midwest    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 16.80% 16.60%
Investment Owned, at Fair Value | Geographic Regions Risk | Canada    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 2.20% 1.70%
Total debt    
Summary of Investment Holdings [Line Items]    
Cost $ 831,475 $ 745,848
Fair Value $ 761,412 $ 669,799
Total debt | Investment Owned, at Cost | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 70.40% 70.80%
Total debt | Investment Owned, at Fair Value | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 53.20% 51.20%
Secured First Lien Debt    
Summary of Investment Holdings [Line Items]    
Cost $ 678,035 $ 593,008
Fair Value $ 654,079 $ 570,602
Secured First Lien Debt | Investment Owned, at Cost | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 57.40% 56.30%
Secured First Lien Debt | Investment Owned, at Fair Value | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 45.70% 43.60%
Secured Second Lien Debt    
Summary of Investment Holdings [Line Items]    
Cost $ 153,440 $ 152,840
Fair Value $ 107,333 $ 99,197
Secured Second Lien Debt | Investment Owned, at Cost | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 13.00% 14.50%
Secured Second Lien Debt | Investment Owned, at Fair Value | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 7.50% 7.60%
Total equity/equivalents    
Summary of Investment Holdings [Line Items]    
Cost $ 349,604 $ 307,000
Fair Value $ 669,453 $ 639,449
Total equity/equivalents | Investment Owned, at Cost | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 29.60% 29.20%
Total equity/equivalents | Investment Owned, at Fair Value | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 46.80% 48.80%
Preferred equity    
Summary of Investment Holdings [Line Items]    
Cost $ 300,007 $ 257,403
Fair Value $ 484,076 $ 426,949
Preferred equity | Investment Owned, at Cost | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 25.40% 24.50%
Preferred equity | Investment Owned, at Fair Value | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 33.80% 32.60%
Common equity/equivalents    
Summary of Investment Holdings [Line Items]    
Cost $ 49,597 $ 49,597
Fair Value $ 185,377 $ 212,500
Common equity/equivalents | Investment Owned, at Cost | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 4.20% 4.70%
Common equity/equivalents | Investment Owned, at Fair Value | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 13.00% 16.20%
[1] Cumulative gross unrealized appreciation for federal income tax purposes is $428.5 million; cumulative gross unrealized depreciation for federal income tax purposes is $173.7 million. Cumulative net unrealized appreciation is $254.8 million, based on a tax cost of $1.1 billion.