v3.25.2
Borrowings - Narrative (Details)
3 Months Ended 6 Months Ended
Feb. 12, 2025
USD ($)
Feb. 28, 2022
USD ($)
Mar. 01, 2021
USD ($)
Mar. 19, 2020
USD ($)
Jun. 30, 2025
USD ($)
Jun. 30, 2024
USD ($)
Jun. 30, 2025
USD ($)
Jun. 30, 2024
USD ($)
Dec. 31, 2024
USD ($)
Aug. 06, 2024
USD ($)
Aug. 05, 2024
USD ($)
Feb. 28, 2014
USD ($)
Debt Instrument [Line Items]                        
Maximum borrowing amount         $ 675,000,000   $ 675,000,000   $ 695,000,000      
Long-term line of credit         50,000,000   50,000,000   5,000,000      
Deferred credit facility costs         3,096,000   3,096,000   3,904,000      
Credit facility, average outstanding borrowings         $ 29,700,000 $ 53,900,000 $ 17,400,000 $ 57,800,000        
Credit facility, average interest rate         8.30% 9.02% 8.30% 9.02%        
Assets         $ 788,250,000   $ 788,250,000   763,040,000      
Debt fair value         422,167,000   422,167,000   387,995,000      
Asset Pledged as Collateral                        
Debt Instrument [Line Items]                        
Assets         334,700,000   334,700,000   332,000,000.0      
Asset Not Pledged as Collateral                        
Debt Instrument [Line Items]                        
Assets         453,600,000   453,600,000   431,000,000.0      
Unsecured Debt | 2025 Notes                        
Debt Instrument [Line Items]                        
Maximum borrowing amount         0   $ 0   70,000,000      
Deferred credit facility costs                 100,000      
Face amount       $ 70,000,000                
Interest rate       4.50%                
Repayments of debt       $ 70,000,000                
Asset coverage ratio, minimum             1.50          
Interest coverage ratio, minimum             1.25          
Minimum stockholders' equity balance         216,100,000   $ 216,100,000          
Upward adjustment, percent of issuance proceeds             65.00%          
Unsecured Debt | 2026 Notes                        
Debt Instrument [Line Items]                        
Maximum borrowing amount         200,000,000   $ 200,000,000   200,000,000      
Deferred credit facility costs         300,000   300,000   500,000      
Face amount     $ 200,000,000                  
Interest rate     4.50%                  
Debt fair value         198,900,000   198,900,000   194,800,000      
Aggregate principal balance, secured status threshold     $ 25,000,000                  
Interest rate, below investment grade event     5.50%                  
Debt term     5 years                  
Unsecured Debt | 2027 Notes                        
Debt Instrument [Line Items]                        
Maximum borrowing amount         125,000,000   125,000,000   125,000,000      
Deferred credit facility costs         500,000   500,000   600,000      
Face amount   $ 125,000,000                    
Interest rate   5.00%                    
Debt fair value         122,300,000   122,300,000   119,000,000.0      
Aggregate principal balance, secured status threshold   $ 25,000,000                    
Interest rate, below investment grade event   6.00%                    
Debt term   5 years                    
Unsecured Debt | 2028 Notes                        
Debt Instrument [Line Items]                        
Maximum borrowing amount         50,000,000   50,000,000   0      
Deferred credit facility costs         600,000   600,000          
Face amount $ 50,000,000                      
Interest rate 8.11%                      
Asset coverage ratio, minimum 1.50                      
Interest coverage ratio, minimum 1.25                      
Minimum stockholders' equity balance $ 236,776,000                      
Upward adjustment, percent of issuance proceeds 65.00%                      
Debt fair value         52,400,000   $ 52,400,000          
Aggregate principal balance, secured status threshold $ 25,000,000                      
Interest rate, below investment grade event 1.00%                      
Ratio calculation period 6 months                      
Debt term             3 years          
Revolving Credit Facility | Line of Credit                        
Debt Instrument [Line Items]                        
Maximum borrowing amount         300,000,000   $ 300,000,000   300,000,000 $ 300,000,000 $ 350,000,000 $ 150,000,000
Current borrowing capacity         300,000,000   300,000,000          
Accordion feature, higher borrowing capacity option         400,000,000   $ 400,000,000          
Debt instrument, variable interest rate, type flag             Secured Overnight Financing Rate (SOFR) [Member]          
Floor interest rate             0.50%          
Unused commitment fee percentage             0.50%          
Long-term line of credit         50,000,000   $ 50,000,000   5,000,000      
Deferred credit facility costs         3,100,000   3,100,000   3,900,000      
Debt fair value         $ 50,000,000   $ 50,000,000   $ 5,000,000      
Revolving Credit Facility | Line of Credit | Maximum                        
Debt Instrument [Line Items]                        
Advance rate             50.00%          
Revolving Credit Facility | Line of Credit | Greater than or equal to 75%                        
Debt Instrument [Line Items]                        
Basis spread on variable rate             3.20%          
Facility utilization percentage             75.00%          
Revolving Credit Facility | Line of Credit | Greater than or equal to 50%                        
Debt Instrument [Line Items]                        
Basis spread on variable rate             3.35%          
Revolving Credit Facility | Line of Credit | Greater than or equal to 50% | Minimum                        
Debt Instrument [Line Items]                        
Facility utilization percentage             50.00%          
Revolving Credit Facility | Line of Credit | Greater than or equal to 50% | Maximum                        
Debt Instrument [Line Items]                        
Facility utilization percentage             75.00%          
Revolving Credit Facility | Line of Credit | Less than 50%                        
Debt Instrument [Line Items]                        
Basis spread on variable rate             3.50%          
Facility utilization percentage             50.00%          
Revolving Credit Facility | Line of Credit | During amortization period                        
Debt Instrument [Line Items]                        
Basis spread on variable rate             4.50%