Quarterly report [Sections 13 or 15(d)]

INVESTMENTS - Schedule of Investment Concentrations (Details)

v3.26.1
INVESTMENTS - Schedule of Investment Concentrations (Details) - USD ($)
$ in Thousands
 3 Months Ended 12 Months Ended
Jun. 30, 2026
Mar. 31, 2026
Summary of Investment Holdings [Line Items]    
Cost $ 1,044,448 $ 1,052,848 [1]
Fair Value 1,282,020 1,309,248 [1]
South    
Summary of Investment Holdings [Line Items]    
Fair Value 616,300 649,436
West    
Summary of Investment Holdings [Line Items]    
Fair Value 224,589 227,294
Midwest    
Summary of Investment Holdings [Line Items]    
Fair Value 218,088 216,726
Northeast    
Summary of Investment Holdings [Line Items]    
Fair Value 199,303 193,837
Canada    
Summary of Investment Holdings [Line Items]    
Fair Value 23,740 21,955
Machinery (Non-Agriculture, Non-Construction, and Non-Electronic)    
Summary of Investment Holdings [Line Items]    
Fair Value 222,005 258,692
Diversified/Conglomerate Services    
Summary of Investment Holdings [Line Items]    
Fair Value 194,037 189,148
Home and Office Furnishings, Housewares, and Durable Consumer Products    
Summary of Investment Holdings [Line Items]    
Fair Value 173,346 166,553
Aerospace and Defense    
Summary of Investment Holdings [Line Items]    
Fair Value 169,054 174,542
Oil and Gas    
Summary of Investment Holdings [Line Items]    
Fair Value 123,550 125,605
Leisure, Amusement, Motion Pictures, and Entertainment    
Summary of Investment Holdings [Line Items]    
Fair Value 110,550 105,339
Buildings and Real Estate    
Summary of Investment Holdings [Line Items]    
Fair Value 64,830 68,987
Electronics    
Summary of Investment Holdings [Line Items]    
Fair Value 62,968 62,723
Chemicals, Plastics, and Rubber    
Summary of Investment Holdings [Line Items]    
Fair Value 52,499 49,715
Healthcare, Education, and Childcare    
Summary of Investment Holdings [Line Items]    
Fair Value 41,823 41,630
Mining, Steel, Iron and Non-Precious Metals    
Summary of Investment Holdings [Line Items]    
Fair Value 40,574 37,713
Telecommunications    
Summary of Investment Holdings [Line Items]    
Fair Value 7,459 7,942
Other less than 2.0%    
Summary of Investment Holdings [Line Items]    
Fair Value $ 19,325 $ 20,659
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 | Machinery (Non-Agriculture, Non-Construction, and Non-Electronic)    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 17.30% 19.80%
Investment Owned, at Fair Value | Industry Concentration Risk | Diversified/Conglomerate Services    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 15.10% 14.40%
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 13.50% 12.70%
Investment Owned, at Fair Value | Industry Concentration Risk | Aerospace and Defense    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 13.20% 13.40%
Investment Owned, at Fair Value | Industry Concentration Risk | Oil and Gas    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 9.60% 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 8.60% 8.00%
Investment Owned, at Fair Value | Industry Concentration Risk | Buildings and Real Estate    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 5.10% 5.30%
Investment Owned, at Fair Value | Industry Concentration Risk | Electronics    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 4.90% 4.80%
Investment Owned, at Fair Value | Industry Concentration Risk | Chemicals, Plastics, and Rubber    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 4.10% 3.80%
Investment Owned, at Fair Value | Industry Concentration Risk | Healthcare, Education, and Childcare    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 3.30% 3.20%
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 3.20% 2.90%
Investment Owned, at Fair Value | Industry Concentration Risk | Telecommunications    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 0.60% 0.60%
Investment Owned, at Fair Value | Industry Concentration Risk | Other less than 2.0%    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 1.50% 1.50%
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 48.10% 49.60%
Investment Owned, at Fair Value | Geographic Regions Risk | West    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 17.50% 17.30%
Investment Owned, at Fair Value | Geographic Regions Risk | Midwest    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 17.00% 16.60%
Investment Owned, at Fair Value | Geographic Regions Risk | Northeast    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 15.50% 14.80%
Investment Owned, at Fair Value | Geographic Regions Risk | Canada    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 1.90% 1.70%
Total debt    
Summary of Investment Holdings [Line Items]    
Cost $ 737,448 $ 745,848
Fair Value $ 667,420 $ 669,799
Total debt | Investment Owned, at Cost | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 70.60% 70.80%
Total debt | Investment Owned, at Fair Value | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 52.10% 51.20%
Secured First Lien Debt    
Summary of Investment Holdings [Line Items]    
Cost $ 584,008 $ 593,008
Fair Value $ 564,631 $ 570,602
Secured First Lien Debt | Investment Owned, at Cost | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 55.90% 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 44.00% 43.60%
Secured Second Lien Debt    
Summary of Investment Holdings [Line Items]    
Cost $ 153,440 $ 152,840
Fair Value $ 102,789 $ 99,197
Secured Second Lien Debt | Investment Owned, at Cost | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 14.70% 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 8.10% 7.60%
Total equity/equivalents    
Summary of Investment Holdings [Line Items]    
Cost $ 307,000 $ 307,000
Fair Value $ 614,600 $ 639,449
Total equity/equivalents | Investment Owned, at Cost | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 29.40% 29.20%
Total equity/equivalents | Investment Owned, at Fair Value | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 47.90% 48.80%
Preferred equity    
Summary of Investment Holdings [Line Items]    
Cost $ 257,403 $ 257,403
Fair Value $ 429,510 $ 426,949
Preferred equity | Investment Owned, at Cost | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 24.70% 24.50%
Preferred equity | Investment Owned, at Fair Value | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 33.50% 32.60%
Common equity/equivalents    
Summary of Investment Holdings [Line Items]    
Cost $ 49,597 $ 49,597
Fair Value $ 185,090 $ 212,500
Common equity/equivalents | Investment Owned, at Cost | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 4.70% 4.70%
Common equity/equivalents | Investment Owned, at Fair Value | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Percentage of Total Investments 14.40% 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.