v3.26.1
Agreements and Related Party Transactions - Additional Information (Details) - USD ($)
 3 Months Ended 6 Months Ended 12 Months Ended
Mar. 31, 2026
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Dec. 31, 2025
Related Party Transaction [Line Items]            
Administrative services expenses   $ 436,000 $ 445,000 $ 872,000 $ 890,000  
Other payable to administrator   574,000   $ 574,000   $ 592,000
Annual base management fee calculation in percentage of gross assets 1.25%     1.00%    
Management fee, description       Under the terms of the Investment Advisory Agreement, the Adviser has voluntarily waived its right to receive management fees on the Company’s investments in WhiteHawk III Onshore Fund LP and Freeport Financial SBIC Fund LP for any period in which these investments remain in the investment portfolio.    
Management fee   3,977,000 5,089,000 $ 8,899,000 10,127,000  
Management fees waiver   5,000 13,000 12,000 33,000  
Management fees payable   3,972,000   $ 3,972,000   5,037,000
Income incentive fee percent payable quarterly in excess of pre-incentive fee net investment income       100.00%    
Income incentive fee quarterly return on investment income percent       1.75%    
Income incentive fee annual return on investment income percent       7.00%    
Percent of pre-incentive fee net investment income received to obtain catch-up feature 17.50%     15.00%    
Pre-incentive fee net investment income percent catch-up 2.1212%     2.0588%    
Pre-incentive fee net investment income percent in excess of catch-up 17.50%     15.00%    
Capital gains incentive fee percent payable annually 17.50%     15.00%    
Income incentive fee incurred   2,307,000 3,579,000 $ 5,295,000 7,098,000  
Income incentive fee waived   29,000 23,000 1,441,000 55,000  
Income incentive fees unpaid       $ 2,279,000   $ 3,468,000
Incentive fee on cumulative unrealized capital appreciation description.       This accrual is calculated using the aggregate cumulative realized capital gains and losses and aggregate cumulative unrealized capital appreciation or depreciation. If such amount is positive at the end of a period, then the Company records a capital gains incentive fee equal to 15.0% of such amount, minus the aggregate amount of actual incentive fees based on capital gains paid in all prior periods. If such amount is negative, then there is no accrual for such period. There can be no assurance that such unrealized capital appreciation will be realized in the future    
Capital gains incentive fees on unrealized capital appreciation   $ 0 $ 0 $ 0 $ 0  
Percentage of outstanding common stock owned   2.93%   2.93%   2.83%
Capital gains incentive fees remain outstanding       $ 0   $ 0
Non-controlled Affiliated Investments            
Related Party Transaction [Line Items]            
Percentage of outstanding voting securities owned       5.00%   5.00%
Controlled Investments            
Related Party Transaction [Line Items]            
Percentage of outstanding voting securities owned       25.00%   25.00%
Minimum | Non-controlled Affiliated Investments            
Related Party Transaction [Line Items]            
Percentage of outstanding voting securities owned       5.00%    
Minimum | Controlled Investments            
Related Party Transaction [Line Items]            
Percentage of outstanding voting securities owned       25.00%    
Sun Life Financial Inc            
Related Party Transaction [Line Items]            
Percentage of outstanding common stock owned   6.04%   6.04%   6.02%
Sun Life Financial Inc | 2028 Unsecured Notes            
Related Party Transaction [Line Items]            
Participating lender amount       $ 2,000,000    
Sun Life Financial Inc | 2029 Unsecured Notes            
Related Party Transaction [Line Items]            
Participating lender amount       10,000,000    
Sun Life Financial Inc | 2030 Unsecured Notes            
Related Party Transaction [Line Items]            
Participating lender amount       $ 10,000,000