Quarterly report [Sections 13 or 15(d)]

RELATED PARTY TRANSACTIONS - Narrative (Details)

v3.26.1
RELATED PARTY TRANSACTIONS - Narrative (Details)
$ in Thousands
 3 Months Ended 12 Months Ended
Jan. 29, 2025
Dec. 11, 2024
Oct. 30, 2020
component
Mar. 31, 2026
USD ($)
shares
Mar. 31, 2025
USD ($)
Dec. 31, 2025
USD ($)
Jan. 20, 2025
Related Party Transaction [Line Items]              
Total expenses, net of expense waivers       $ 16,846 $ 16,439    
Incentive fee on capital gains       $ 638 0    
Share repurchase program, percentage of outstanding stock maximum             3.00%
Related Party | Main Street              
Related Party Transaction [Line Items]              
Units (in shares) | shares       2,025,220      
MSC Income | Advisory Agreement              
Related Party Transaction [Line Items]              
Advisory agreement   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) 7.50%            
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) 1.00%            
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 | Advisory Agreement - Subordinated Incentive Fees | Related Party              
Related Party Transaction [Line Items]              
Total expenses, net of expense waivers       $ 2,100   $ 2,800  
MSC Income | Advisory Agreement - Incentive Fees, Capital Gains Fees | Related Party              
Related Party Transaction [Line Items]              
Incentive fee on capital gains       $ 638 $ 0