Quarterly report [Sections 13 or 15(d)]

INVESTMENTS - Narrative (Details)

v3.25.4
INVESTMENTS - Narrative (Details)
$ in Thousands
 1 Months Ended 3 Months Ended 9 Months Ended
Dec. 31, 2025
USD ($)
portfolioCompany
industry
state
Sep. 30, 2025
USD ($)
Jul. 31, 2025
USD ($)
May 31, 2025
USD ($)
Dec. 31, 2025
USD ($)
portfolioCompany
industry
state
Dec. 31, 2024
USD ($)
Dec. 31, 2025
USD ($)
portfolioCompany
industry
state
Dec. 31, 2024
USD ($)
Jun. 30, 2025
USD ($)
Mar. 31, 2025
USD ($)
Summary of Investment Holdings [Line Items]                    
Purchase of investments             $ 171,316 $ 207,192    
Investments, cost $ 1,058,898       $ 1,058,898   1,058,898     $ 939,066 [1]
Net realized gain (loss)         $ 2,180 $ 0 $ (27,758) $ 42,305    
Number of investment portfolio company | portfolioCompany 29       29   29      
Number of states or countries which have invested in the company location | state 20       20   20      
Number of industries that have made investments | industry 16       16   16      
Investments owned, fair value $ 1,222,792       $ 1,222,792   $ 1,222,792     979,320 [1]
Uncollectible receivables allowance, minimum required day for uncollectible adjustment             90 days      
Gross receivables from portfolio companies 2,200       2,200   $ 2,200     2,300
Allowance for uncollectible receivables 1,400       1,400   1,400     1,700
Five Largest Portfolio Investments | Investment Portfolio Benchmark | Customer Concentration Risk                    
Summary of Investment Holdings [Line Items]                    
Investments owned, fair value 463,900       463,900   $ 463,900      
Percentage of total investments             37.90%      
Secured First Lien Debt                    
Summary of Investment Holdings [Line Items]                    
Investments, cost 658,558       658,558   $ 658,558     584,026
Investments owned, fair value 604,516       604,516   604,516     514,334
Preferred Equity                    
Summary of Investment Holdings [Line Items]                    
Investments, cost 257,403       257,403   257,403     201,487
Investments owned, fair value 429,702       $ 429,702   $ 429,702     $ 302,163
Smart Chemical                    
Summary of Investment Holdings [Line Items]                    
Purchase of investments       $ 49,500            
Smart Chemical | Secured First Lien Debt                    
Summary of Investment Holdings [Line Items]                    
Purchase of investments       35,700            
Smart Chemical | Preferred Equity                    
Summary of Investment Holdings [Line Items]                    
Purchase of investments       13,800            
Sun State                    
Summary of Investment Holdings [Line Items]                    
Purchase of investments       12,800            
Sun State | Secured First Lien Debt                    
Summary of Investment Holdings [Line Items]                    
Purchase of investments       9,800            
Sun State | Preferred Equity                    
Summary of Investment Holdings [Line Items]                    
Purchase of investments       $ 3,100            
PSI Molded                    
Summary of Investment Holdings [Line Items]                    
Investments, cost                 $ 10,600  
Global GRAB Technologies, Inc., ("Global GRAB")                    
Summary of Investment Holdings [Line Items]                    
Purchase of investments     $ 67,600              
Global GRAB Technologies, Inc., ("Global GRAB") | Secured First Lien Debt                    
Summary of Investment Holdings [Line Items]                    
Purchase of investments     46,500              
Global GRAB Technologies, Inc., ("Global GRAB") | Preferred Equity                    
Summary of Investment Holdings [Line Items]                    
Purchase of investments     $ 21,100              
J.R. Hobbs                    
Summary of Investment Holdings [Line Items]                    
Purchase of investments   $ 20,000                
Investments, cost   49,900                
Net realized gain (loss)   $ (29,900)                
Rowan Energy, LLC (“Rowan”)                    
Summary of Investment Holdings [Line Items]                    
Purchase of investments 33,100                  
Rowan Energy, LLC (“Rowan”) | Secured First Lien Debt                    
Summary of Investment Holdings [Line Items]                    
Purchase of investments 25,800                  
Rowan Energy, LLC (“Rowan”) | Preferred Equity                    
Summary of Investment Holdings [Line Items]                    
Purchase of investments $ 7,300                  
[1] Cumulative gross unrealized appreciation for federal income tax purposes is $183.3 million; cumulative gross unrealized depreciation for federal income tax purposes is $144.9 million. Cumulative net unrealized appreciation is $38.5 million, based on a tax cost of $940.9 million.