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

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details)

v3.25.1
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details)
$ in Thousands
12 Months Ended
Mar. 31, 2025
USD ($)
segment
Mar. 31, 2024
USD ($)
Summary of Investment Holdings [Line Items]    
Money market funds $ 1,800 $ 1,900
Cost 939,066 [1] 854,290 [2]
Fair Value $ 979,320 [1] 920,504 [2]
Number of reportable segments | segment 1  
B+T Group Acquisition, Inc., Edge Adhesives Holdings Inc., And J.R. Hobbs Co    
Summary of Investment Holdings [Line Items]    
Cost $ 90,200  
Cost percentage 13.10%  
Fair Value $ 50,900  
Fair value percentage 8.20%  
Edge Adhesives Holdings, Inc., J.R. Hobbs Co. and The Mountain    
Summary of Investment Holdings [Line Items]    
Cost   $ 59,100
Cost percentage   9.00%
Fair Value   $ 29,700
Fair value percentage   4.80%
Non-Control/Non-Affiliate investments    
Summary of Investment Holdings [Line Items]    
Investment owned, percent of voting securities 5.00%  
Cost $ 562,371 [3] $ 544,799 [4]
Fair Value 648,589 [3] 622,233 [4]
Affiliate investments    
Summary of Investment Holdings [Line Items]    
Cost 359,286 [5] 292,082 [6]
Fair Value $ 330,388 [5] 295,366 [6]
Affiliate investments | Minimum    
Summary of Investment Holdings [Line Items]    
Investment owned, percent of voting securities 5.00%  
Affiliate investments | Maximum    
Summary of Investment Holdings [Line Items]    
Investment owned, percent of voting securities 25.00%  
Control investments    
Summary of Investment Holdings [Line Items]    
Investment owned, percent of voting securities 25.00%  
Cost $ 17,409 [7] 17,409 [8]
Fair Value $ 343 [7] $ 2,905 [8]
[1] Cumulative gross unrealized appreciation for federal income tax purposes is $183.3 million; cumulative gross unrealized depreciation for federal income tax purposes is $144.9 million. Cumulative net unrealized appreciation is $38.5 million, based on a tax cost of $940.9 million.
[2] Cumulative gross unrealized appreciation for federal income tax purposes is $180.5 million; cumulative gross unrealized depreciation for federal income tax purposes is $115.8 million. Cumulative net unrealized appreciation is $64.7 million, based on a tax cost of $855.8 million.
[3] Non-Control/Non-Affiliate investments, as defined by the 1940 Act, are those that are neither Control nor Affiliate investments and in which we own less than 5.0% of the issued and outstanding voting securities.
[4] Non-Control/Non-Affiliate investments, as defined by the 1940 Act, are those that are neither Control nor Affiliate investments and in which we own less than 5.0% of the issued and outstanding voting securities.
[5] Affiliate investments, as defined by the 1940 Act, are those that are not Control investments and in which we own, with the power to vote, between and inclusive of 5.0% and 25.0% of the issued and outstanding voting securities.
[6] Affiliate investments, as defined by the 1940 Act, are those that are not Control investments and in which we own, with the power to vote, between and inclusive of 5.0% and 25.0% of the issued and outstanding voting securities.
[7] Control investments, as defined by the 1940 Act, are those where we have the power to exercise a controlling influence over the management or policies of the portfolio company, which may include owning, with the power to vote, more than 25.0% of the issued and outstanding voting securities.
[8] Control investments, as defined by the 1940 Act, are those where we have the power to exercise a controlling influence over the management or policies of the portfolio company, which may include owning, with the power to vote, more than 25.0% of the issued and outstanding voting securities.