Quarterly report pursuant to Section 13 or 15(d)

RELATED PARTY TRANSACTIONS (Details)

v3.22.2.2
RELATED PARTY TRANSACTIONS (Details) - Affiliated Entity - USD ($)
$ in Millions
1 Months Ended 9 Months Ended
Dec. 29, 2021
Mar. 31, 2022
Feb. 28, 2022
Dec. 31, 2020
Sep. 30, 2022
May 31, 2022
External Investment Manager            
Related Party Transaction [Line Items]            
Receivable         $ 6.2  
MSC Income            
Related Party Transaction [Line Items]            
Shares acquired (in shares)         94,697 94,697
Operating Expenses and Amount Due From Tax Sharing Agreement | External Investment Manager            
Related Party Transaction [Line Items]            
Receivable         $ 4.6  
Dividends Declared But Not Yet Paid | External Investment Manager            
Related Party Transaction [Line Items]            
Receivable         1.6  
Investment Management Agreement | Private Loan Fund            
Related Party Transaction [Line Items]            
Amount of transaction     $ 15.0 $ 10.0    
Funded commitments         14.3  
Unfunded commitments         0.7  
Unsecured Revolving Promissory Note | Private Loan Fund            
Related Party Transaction [Line Items]            
Amount of transaction $ 85.0          
Interest rate 5.00%          
Secured Revolving Promissory Note | Private Loan Fund            
Related Party Transaction [Line Items]            
Amount of transaction   $ 10.0        
Interest rate   5.00%        
Unused capacity, commitment fee percentage   0.25%        
2015 Deferred Compensation Plan            
Related Party Transaction [Line Items]            
Amount of transaction         $ 14.0  
2015 Deferred Compensation Plan | Common Stock            
Related Party Transaction [Line Items]            
Deferred compensation (in shares)         161,814  
2015 Deferred Compensation Plan | Phantom Stock Units            
Related Party Transaction [Line Items]            
Amount of transaction         $ 5.4