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

RELATED PARTY TRANSACTIONS - Narrative (Details)

v3.25.4
RELATED PARTY TRANSACTIONS - Narrative (Details)
$ in Thousands
 12 Months Ended
Jan. 29, 2025
Dec. 11, 2024
Oct. 30, 2020
component
Dec. 31, 2025
USD ($)
shares
Dec. 31, 2024
USD ($)
Dec. 31, 2023
USD ($)
Related Party Transaction [Line Items]            
Management fee expense       $ 19,757 $ 20,922 $ 19,828
Accounts payable and other liabilities       $ 3,549 4,723  
Related Party | Main Street            
Related Party Transaction [Line Items]            
Shares acquired (in shares) | shares       1,642,635    
MSC Income | Advisory Agreement            
Related Party Transaction [Line Items]            
Effective period   2 years        
MSC Income | Advisory Agreement | Related Party            
Related Party Transaction [Line Items]            
Base fee rate (as a percent) 1.25%   1.75% 1.50%    
Number of components related to incentive fee | component     2      
Advisory agreement, average total assets threshold (as a percent) 0.075          
MSC Income | Advisory Agreement, Incentive Rate, Pre-Incentive Fee Net Investment Income | Related Party            
Related Party Transaction [Line Items]            
Incentive fee rate (as a percent) 17.50%   20.00%      
MSC Income | Advisory Agreement - Incentive Rate, Quarterly Hurdle Rate | Related Party            
Related Party Transaction [Line Items]            
Base fee rate (as a percent) 20.00%          
Incentive fee rate (as a percent) 1.50%   1.875%      
Advisory agreement, average total assets threshold (as a percent) 0.0100          
MSC Income | Advisory Agreement - Incentive Rate, Annualized Hurdle Rate | Related Party            
Related Party Transaction [Line Items]            
Incentive fee rate (as a percent) 6.00%   7.50%      
MSC Income | Advisory Agreement, Incentive Rate, Pre-Incentive Fee Net Investment Income Below Catch-Up Threshold | Related Party            
Related Party Transaction [Line Items]            
Incentive fee rate (as a percent) 50.00%   100.00%      
MSC Income | Advisory Agreement - Incentive Rate, Quarterly Catch-Up Threshold | Related Party            
Related Party Transaction [Line Items]            
Incentive fee rate (as a percent) 2.30769%   2.34375%      
MSC Income | Advisory Agreement - Incentive Rate, Annualized Catch-Up Threshold | Related Party            
Related Party Transaction [Line Items]            
Incentive fee rate (as a percent) 9.23077%   9.375%      
MSC Income | Advisory Agreement - Incentive Rate, Pre-Incentive Fee Net Investment Income Exceeds Catch-Up Threshold | Related Party            
Related Party Transaction [Line Items]            
Incentive fee rate (as a percent) 17.50%   20.00%      
MSC Income | Investment Management Agreement Incentive Rate, Annualize Hurdle Rate | Related Party            
Related Party Transaction [Line Items]            
Incentive fee rate (as a percent) 6.00%          
MSC Income | Advisory Agreement - Incentive Fees, Capital Gains Fees | Related Party            
Related Party Transaction [Line Items]            
Management fee expense       $ 2,763 $ 0 0
MSC Income - HMS Adviser | Offering Costs | Related Party            
Related Party Transaction [Line Items]            
Percentage of payment of offering costs (as a percent)       1.50%    
Accounts payable and other liabilities       $ 600    
Fee paid indirectly           $ 100