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

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details)

v3.25.3
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details)
$ in Thousands
 12 Months Ended
Apr. 04, 2024
Sep. 30, 2025
USD ($)
segment
investment
loan
Sep. 30, 2024
USD ($)
loan
investment
Sep. 30, 2023
USD ($)
Summary of Investment Holdings [Line Items]        
Reverse stock split, conversion ratio 0.5      
Cost   $ 876,614 [1] $ 771,011 [2]  
Fair Value   859,124 [1] 796,260 [2]  
Total interest income (excluding PIK interest income)   82,291 87,618 $ 79,480
PIK interest income   $ 4,990 5,676 3,550
Investment company, target percentage of taxable income to distribute to shareholders (up to)   100.00%    
Number of reporting segments | segment   1    
OID        
Summary of Investment Holdings [Line Items]        
Fair Value   $ 200 $ 600  
Number of loans | loan   2 2  
Total interest income (excluding PIK interest income)   $ 400 $ 400 200
PIK        
Summary of Investment Holdings [Line Items]        
Number of investments | investment   9 8  
Proceeds from interest received   $ 7,200 $ 200 $ 1,100
B+T Group Acquisition, Inc., Edge Adhesives Holdings, Inc,. And WB Xcel Holdings, LLC        
Summary of Investment Holdings [Line Items]        
Cost   $ 28,800 $ 28,300  
Cost percentage   3.60% 4.10%  
Fair Value   $ 13,000 $ 12,800  
Fair value percentage   1.70% 1.90%  
[1] Cumulative gross unrealized depreciation for federal income tax purposes is $59.7 million; cumulative gross unrealized appreciation for federal income tax purposes is $34.1 million. Cumulative net unrealized depreciation is $25.5 million, based on a tax cost of $884.7 million.
[2] 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