Quarterly report pursuant to Section 13 or 15(d)

INVESTMENTS - Investment Holdings (Details)

v3.23.3
INVESTMENTS - Investment Holdings (Details) - USD ($)
$ in Thousands
 6 Months Ended 12 Months Ended
Sep. 30, 2023
Mar. 31, 2023
Summary of Investment Holdings [Line Items]    
Cost $ 834,798 $ 720,630 [1]
Fair Value 915,636 753,543 [1]
Northeast    
Summary of Investment Holdings [Line Items]    
Fair Value 297,413 266,612
South    
Summary of Investment Holdings [Line Items]    
Fair Value 260,132 171,056
West    
Summary of Investment Holdings [Line Items]    
Fair Value 224,107 197,989
Midwest    
Summary of Investment Holdings [Line Items]    
Fair Value 133,984 117,886
Diversified/Conglomerate Services    
Summary of Investment Holdings [Line Items]    
Fair Value 332,982 268,954
Home and Office Furnishings, Housewares, and Durable Consumer Products    
Summary of Investment Holdings [Line Items]    
Fair Value 153,495 143,685
Hotels, Motels, Inns, and Gaming    
Summary of Investment Holdings [Line Items]    
Fair Value 80,976 58,713
Buildings and Real Estate    
Summary of Investment Holdings [Line Items]    
Fair Value 58,696 60,571
Healthcare, Education, and Childcare    
Summary of Investment Holdings [Line Items]    
Fair Value 48,008 37,445
Oil and Gas    
Summary of Investment Holdings [Line Items]    
Fair Value 45,983 0
Leisure, Amusement, Motion Pictures, and Entertainment    
Summary of Investment Holdings [Line Items]    
Fair Value 38,509 47,616
Mining, Steel, Iron and Non-Precious Metals    
Summary of Investment Holdings [Line Items]    
Fair Value 27,490 25,998
Machinery (Non-Agriculture, Non-Construction, and Non-Electronic)    
Summary of Investment Holdings [Line Items]    
Fair Value 26,705 20,088
Aerospace and Defense    
Summary of Investment Holdings [Line Items]    
Fair Value 25,696 22,215
Chemicals, Plastics, and Rubber    
Summary of Investment Holdings [Line Items]    
Fair Value 23,657 24,891
Printing and Publishing    
Summary of Investment Holdings [Line Items]    
Fair Value 15,275 0
Cargo Transport    
Summary of Investment Holdings [Line Items]    
Fair Value 14,157 14,707
Telecommunications    
Summary of Investment Holdings [Line Items]    
Fair Value 13,692 18,987
Other    
Summary of Investment Holdings [Line Items]    
Fair Value $ 10,315 $ 9,673
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 | Diversified/Conglomerate Services    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 36.40% 35.70%
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 16.80% 19.10%
Investment Owned, At Fair Value | Industry Concentration Risk | Hotels, Motels, Inns, and Gaming    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 8.80% 7.80%
Investment Owned, At Fair Value | Industry Concentration Risk | Buildings and Real Estate    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 6.40% 8.00%
Investment Owned, At Fair Value | Industry Concentration Risk | Healthcare, Education, and Childcare    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 5.20% 5.00%
Investment Owned, At Fair Value | Industry Concentration Risk | Oil and Gas    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 5.00% 0.00%
Investment Owned, At Fair Value | Industry Concentration Risk | Leisure, Amusement, Motion Pictures, and Entertainment    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 4.20% 6.30%
Investment Owned, At Fair Value | Industry Concentration Risk | Mining, Steel, Iron and Non-Precious Metals    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 3.00% 3.50%
Investment Owned, At Fair Value | Industry Concentration Risk | Machinery (Non-Agriculture, Non-Construction, and Non-Electronic)    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 2.90% 2.70%
Investment Owned, At Fair Value | Industry Concentration Risk | Aerospace and Defense    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 2.80% 2.80%
Investment Owned, At Fair Value | Industry Concentration Risk | Chemicals, Plastics, and Rubber    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 2.60% 3.30%
Investment Owned, At Fair Value | Industry Concentration Risk | Printing and Publishing    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 1.70% 0.00%
Investment Owned, At Fair Value | Industry Concentration Risk | Cargo Transport    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 1.60% 2.00%
Investment Owned, At Fair Value | Industry Concentration Risk | Telecommunications    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 1.50% 2.50%
Investment Owned, At Fair Value | Industry Concentration Risk | Other    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 1.10% 1.30%
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 | Northeast    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 32.50% 35.40%
Investment Owned, At Fair Value | Geographic Regions Risk | South    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 28.40% 22.70%
Investment Owned, At Fair Value | Geographic Regions Risk | West    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 24.50% 26.30%
Investment Owned, At Fair Value | Geographic Regions Risk | Midwest    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 14.60% 15.60%
Debt Securities    
Summary of Investment Holdings [Line Items]    
Cost $ 650,697 $ 555,597
Fair Value $ 611,251 $ 513,251
Debt Securities | Investment Owned, At Cost | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 78.00% 77.10%
Debt Securities | Investment Owned, At Fair Value | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 66.70% 68.20%
Secured First Lien Debt    
Summary of Investment Holdings [Line Items]    
Cost $ 541,539 $ 471,439
Fair Value $ 508,504 $ 437,517
Secured First Lien Debt | Investment Owned, At Cost | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 64.90% 65.40%
Secured First Lien Debt | Investment Owned, At Fair Value | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 55.50% 58.10%
Secured Second Lien Debt    
Summary of Investment Holdings [Line Items]    
Cost $ 109,158 $ 84,158
Fair Value $ 102,747 $ 75,734
Secured Second Lien Debt | Investment Owned, At Cost | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 13.10% 11.70%
Secured Second Lien Debt | Investment Owned, At Fair Value | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 11.20% 10.10%
Equity Securities    
Summary of Investment Holdings [Line Items]    
Cost $ 184,101 $ 165,033
Fair Value $ 304,385 $ 240,292
Equity Securities | Investment Owned, At Cost | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 22.00% 22.90%
Equity Securities | Investment Owned, At Fair Value | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 33.30% 31.80%
Preferred Equity    
Summary of Investment Holdings [Line Items]    
Cost $ 163,787 $ 149,099
Fair Value $ 267,596 $ 222,585
Preferred Equity | Investment Owned, At Cost | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 19.60% 20.70%
Preferred Equity | Investment Owned, At Fair Value | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 29.30% 29.50%
Common Equity/ Equivalents    
Summary of Investment Holdings [Line Items]    
Cost $ 20,314 $ 15,934
Fair Value $ 36,789 $ 17,707
Common Equity/ Equivalents | Investment Owned, At Cost | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 2.40% 2.20%
Common Equity/ Equivalents | Investment Owned, At Fair Value | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 4.00% 2.30%
[1] Cumulative gross unrealized appreciation for federal income tax purposes is $150.4 million; cumulative gross unrealized depreciation for federal income tax purposes is $119.3 million. Cumulative net unrealized appreciation is $31.1 million, based on a tax cost of $722.4 million.