v3.26.1
Borrowings - Narrative (Details)
1 Months Ended 3 Months Ended
Mar. 02, 2026
USD ($)
Feb. 27, 2026
USD ($)
Nov. 25, 2025
Feb. 12, 2025
USD ($)
Feb. 28, 2022
USD ($)
Mar. 01, 2021
USD ($)
Mar. 31, 2026
USD ($)
Mar. 31, 2025
USD ($)
Mar. 31, 2026
USD ($)
Mar. 31, 2025
USD ($)
Dec. 31, 2025
USD ($)
Sep. 30, 2025
Aug. 06, 2024
USD ($)
Aug. 05, 2024
USD ($)
Mar. 19, 2020
USD ($)
Feb. 28, 2014
USD ($)
Debt Instrument [Line Items]                                
Total Commitment             $ 550,000,000   $ 550,000,000   $ 675,000,000          
Outstanding borrowings under credit facility             197,000,000   197,000,000   95,000,000          
Deferred credit facility costs             4,304,000   4,304,000   4,643,000          
Credit facility, average outstanding borrowings                 $ 131,700,000 $ 5,000,000.0            
Credit facility, average interest rate (in percentage)                 7.11% 8.31%            
Assets             807,089,000   $ 807,089,000   839,649,000          
Debt fair value             445,633,000   445,633,000   472,813,000          
Asset Pledged as Collateral                                
Debt Instrument [Line Items]                                
Assets             417,200,000   417,200,000   427,200,000          
Asset Not Pledged as Collateral                                
Debt Instrument [Line Items]                                
Assets             389,900,000   $ 389,900,000   412,500,000          
Unsecured Debt | 2025 Notes                                
Debt Instrument [Line Items]                                
Face amount                             $ 70,000,000.0  
Stated interest rate                             4.50%  
Repayments of debt               $ 70,000,000.0                
Asset coverage ratio, minimum                 1.50              
Interest coverage ratio, minimum                 1.25              
Minimum stockholders' equity balance             216,100,000   $ 216,100,000              
Upward adjustment, issuance proceeds (in percentage)                 65.00%              
Unsecured Debt | 2026 Notes                                
Debt Instrument [Line Items]                                
Total Commitment             0   $ 0   200,000,000          
Face amount           $ 200,000,000.0                    
Stated interest rate           4.50%                    
Repayments of debt             200,000,000.0                  
Debt term           5 years                    
Debt fair value             0.0   0.0   202,100,000          
Unsecured Debt | 2027 Notes                                
Debt Instrument [Line Items]                                
Total Commitment             125,000,000   125,000,000   125,000,000          
Face amount         $ 125,000,000.0                      
Stated interest rate         5.00%                      
Debt term         5 years                      
Debt fair value             123,000,000.0   123,000,000.0   124,200,000          
Aggregate principal balance, secured status threshold         $ 25,000,000                      
Interest rate, below investment grade event         6.00%                      
Unsecured Debt | 8.11% 2028 Notes                                
Debt Instrument [Line Items]                                
Total Commitment             $ 50,000,000   $ 50,000,000   50,000,000          
Face amount       $ 50,000,000.0                        
Stated interest rate       8.11%     8.11%   8.11%     9.11%        
Asset coverage ratio, minimum       1.50                        
Interest coverage ratio, minimum       1.25                        
Minimum stockholders' equity balance       $ 236,776,000                        
Upward adjustment, issuance proceeds (in percentage)       65.00%                        
Debt term                 3 years              
Debt fair value             $ 51,100,000   $ 51,100,000   52,500,000          
Aggregate principal balance, secured status threshold       $ 25,000,000                        
Interest rate, below investment grade event       1.00%                        
Ratio calculation period       6 months                        
Unsecured Debt | 7.50% 2028 Notes                                
Debt Instrument [Line Items]                                
Total Commitment             75,000,000   75,000,000   0          
Deferred credit facility costs             $ 100,000   $ 100,000              
Face amount                             $ 75,000,000.0  
Stated interest rate   7.50%         7.50%   7.50%              
Repayments of debt $ 200,000,000.0                              
Asset coverage ratio, minimum   1.50                            
Minimum stockholders' equity balance   $ 230,800,000                            
Upward adjustment, issuance proceeds (in percentage)   25.00%                            
Debt term                 3 years              
Debt fair value             $ 75,400,000   $ 75,400,000              
Interest rate, below investment grade event   1.00%                            
Downward adjustment, issuance proceeds (in percentage)   25.00%                            
Interest rate, secured debt ratio event   1.50%                            
Interest rate, below investment grade and secured debt ratio event   2.00%                            
Payment in Kind (PIK) Note | 8.11% 2028 Notes                                
Debt Instrument [Line Items]                                
Ratio calculation period       6 months                        
Paid in kind interest to total interest       35.00%                        
Revolving Credit Facility | Line of Credit                                
Debt Instrument [Line Items]                                
Total Commitment             300,000,000   $ 300,000,000   300,000,000   $ 300,000,000 $ 350,000,000   $ 150,000,000.0
Debt instrument, variable interest rate, type flag     Secured Overnight Financing Rate (SOFR) [Member]           Secured Overnight Financing Rate (SOFR) [Member]              
Floor interest rate     0.50%           0.50%              
Current borrowing capacity             300,000,000   $ 300,000,000              
Accordion feature, higher borrowing capacity option             400,000,000   $ 400,000,000              
Unused commitment fee (in percentage)                 0.50%              
Outstanding borrowings under credit facility             197,000,000.0   $ 197,000,000.0   95,000,000.0          
Deferred credit facility costs             4,300,000   4,300,000   4,600,000          
Debt fair value             $ 197,000,000   $ 197,000,000   $ 95,000,000          
Revolving Credit Facility | Line of Credit | Maximum                                
Debt Instrument [Line Items]                                
Advance rate                 55.00%              
Revolving Credit Facility | Line of Credit | Greater than or equal to 75%                                
Debt Instrument [Line Items]                                
Basis spread on variable rate     2.75%           2.75%              
Facility utilization (in percentage)     75.00%           75.00%              
Revolving Credit Facility | Line of Credit | Greater than or equal to 50%                                
Debt Instrument [Line Items]                                
Basis spread on variable rate     2.85%           2.85%              
Revolving Credit Facility | Line of Credit | Greater than or equal to 50% | Minimum                                
Debt Instrument [Line Items]                                
Facility utilization (in percentage)     50.00%           50.00%              
Revolving Credit Facility | Line of Credit | Greater than or equal to 50% | Maximum                                
Debt Instrument [Line Items]                                
Facility utilization (in percentage)     75.00%           75.00%              
Revolving Credit Facility | Line of Credit | Less than 50%                                
Debt Instrument [Line Items]                                
Basis spread on variable rate     3.00%           3.00%              
Facility utilization (in percentage)     50.00%           50.00%              
Revolving Credit Facility | Line of Credit | During amortization period                                
Debt Instrument [Line Items]                                
Basis spread on variable rate     4.50%           4.50%