Quarterly report pursuant to Section 13 or 15(d)

INVESTMENTS - Summary Investment Holdings (Details)

v3.25.0.1
INVESTMENTS - Summary Investment Holdings (Details) - USD ($)
$ in Thousands
 3 Months Ended 12 Months Ended
Dec. 31, 2024
Sep. 30, 2024
Summary of Investment Holdings [Line Items]    
Cost $ 816,140 $ 771,011 [1]
Fair Value $ 799,497 $ 796,260 [1]
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 | Geographic Regions Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 100.00% 100.00%
West    
Summary of Investment Holdings [Line Items]    
Fair Value $ 269,153 $ 249,082
West | Investment Owned, At Fair Value | Geographic Regions Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 33.70% 31.30%
South    
Summary of Investment Holdings [Line Items]    
Fair Value $ 255,493 $ 314,010
South | Investment Owned, At Fair Value | Geographic Regions Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 31.90% 39.40%
Midwest    
Summary of Investment Holdings [Line Items]    
Fair Value $ 237,470 $ 192,897
Midwest | Investment Owned, At Fair Value | Geographic Regions Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 29.70% 24.20%
Northeast    
Summary of Investment Holdings [Line Items]    
Fair Value $ 37,381 $ 40,271
Northeast | Investment Owned, At Fair Value | Geographic Regions Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 4.70% 5.10%
Healthcare, Education, and Childcare    
Summary of Investment Holdings [Line Items]    
Fair Value $ 219,831 $ 101,707
Healthcare, Education, and Childcare | Investment Owned, At Fair Value | Industry Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 27.50% 12.80%
Diversified/Conglomerate Manufacturing    
Summary of Investment Holdings [Line Items]    
Fair Value $ 168,992 $ 160,264
Diversified/Conglomerate Manufacturing | Investment Owned, At Fair Value | Industry Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 21.10% 20.10%
Diversified/Conglomerate Service    
Summary of Investment Holdings [Line Items]    
Fair Value $ 145,704 $ 179,032
Diversified/Conglomerate Service | Investment Owned, At Fair Value | Industry Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 18.20% 22.50%
Beverage, Food, and Tobacco    
Summary of Investment Holdings [Line Items]    
Fair Value $ 85,303 $ 88,327
Beverage, Food, and Tobacco | Investment Owned, At Fair Value | Industry Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 10.70% 11.10%
Aerospace and Defense    
Summary of Investment Holdings [Line Items]    
Fair Value $ 62,359 $ 153,096
Aerospace and Defense | Investment Owned, At Fair Value | Industry Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 7.80% 19.20%
Automobile    
Summary of Investment Holdings [Line Items]    
Fair Value $ 27,652 $ 28,286
Automobile | Investment Owned, At Fair Value | Industry Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 3.50% 3.60%
Machinery    
Summary of Investment Holdings [Line Items]    
Fair Value $ 23,404 $ 21,816
Machinery | Investment Owned, At Fair Value | Industry Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 2.90% 2.70%
Cargo Transportation    
Summary of Investment Holdings [Line Items]    
Fair Value $ 20,200 $ 20,200
Cargo Transportation | Investment Owned, At Fair Value | Industry Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 2.50% 2.50%
Oil and Gas    
Summary of Investment Holdings [Line Items]    
Fair Value $ 20,007 $ 20,554
Oil and Gas | Investment Owned, At Fair Value | Industry Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 2.50% 2.60%
Personal and Non-Durable Consumer Products    
Summary of Investment Holdings [Line Items]    
Fair Value $ 10,895 $ 13,586
Personal and Non-Durable Consumer Products | Investment Owned, At Fair Value | Industry Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 1.40% 1.70%
Other    
Summary of Investment Holdings [Line Items]    
Fair Value $ 15,150 $ 9,392
Other | Investment Owned, At Fair Value | Industry Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 1.90% 1.20%
Debt Securities    
Summary of Investment Holdings [Line Items]    
Cost $ 739,775 $ 694,625
Fair Value $ 714,002 $ 668,685
Debt Securities | Investment Owned, At Cost | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 90.60% 90.10%
Debt Securities | Investment Owned, At Fair Value | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 89.30% 84.00%
Secured first lien debt    
Summary of Investment Holdings [Line Items]    
Cost $ 612,161 $ 580,736
Fair Value $ 586,409 $ 554,937
Secured first lien debt | Investment Owned, At Cost | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 75.00% 75.30%
Secured first lien debt | Investment Owned, At Fair Value | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 73.40% 69.70%
Secured second lien debt    
Summary of Investment Holdings [Line Items]    
Cost $ 127,094 $ 113,691
Fair Value $ 127,234 $ 113,716
Secured second lien debt | Investment Owned, At Cost | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 15.60% 14.80%
Secured second lien debt | Investment Owned, At Fair Value | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 15.90% 14.30%
Unsecured debt    
Summary of Investment Holdings [Line Items]    
Cost $ 520 $ 198
Fair Value $ 359 $ 32
Unsecured debt | Investment Owned, At Cost | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 0.00% 0.00%
Unsecured debt | Investment Owned, At Fair Value | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 0.00% 0.00%
Equity Securities    
Summary of Investment Holdings [Line Items]    
Cost $ 76,365 $ 76,386
Fair Value $ 85,495 $ 127,575
Equity Securities | Investment Owned, At Cost | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 9.40% 9.90%
Equity Securities | Investment Owned, At Fair Value | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 10.70% 16.00%
Preferred Equity    
Summary of Investment Holdings [Line Items]    
Cost $ 44,279 $ 45,017
Fair Value $ 31,294 $ 31,346
Preferred Equity | Investment Owned, At Cost | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 5.40% 5.80%
Preferred Equity | Investment Owned, At Fair Value | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 3.90% 3.90%
Common Equity/ Equivalents    
Summary of Investment Holdings [Line Items]    
Cost $ 32,086 $ 31,369
Fair Value $ 54,201 $ 96,229
Common Equity/ Equivalents | Investment Owned, At Cost | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 4.00% 4.10%
Common Equity/ Equivalents | Investment Owned, At Fair Value | Investment Type Concentration Risk    
Summary of Investment Holdings [Line Items]    
Concentration risk, percentage 6.80% 12.10%
[1] 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.