v3.26.1
Borrowings - Details 1 (Details) - USD ($)
 3 Months Ended 12 Months Ended
May 31, 2026
Feb. 28, 2026
Nov. 06, 2025
May 31, 2025
Jun. 14, 2024
Apr. 04, 2022
Jan. 28, 2021
Dec. 29, 2020
Jul. 09, 2020
May 31, 2026
May 31, 2025
Feb. 28, 2026
Mar. 31, 2026
Mar. 27, 2025
Sep. 29, 2022
Aug. 14, 2019
Mar. 23, 2018
Borrowings [Line Items]                                  
Employ leverage, percentage                   200.00%              
Asset coverage ratio 162.60% 168.40%               162.60%   168.40%          
Borrowings outstanding $ 796,700,000     $ 792,800,000           $ 796,700,000 $ 792,800,000            
Weighted average interest rate 6.13%     5.58%           6.13% 5.58%            
Percentage of credit facility                   0.75%              
Administrative agent fee                   $ 1,350,000 $ 1,250,000            
Amortization of deferred financing cost                   $ 0 100,000            
Outstanding percentage rate 1.00%                 1.00%              
Line of credit facility minimum drawn amount $ 70,600,000                 $ 70,600,000              
Securitized credit facility 70,000,000 $ 70,000,000               70,000,000   $ 70,000,000          
Commitment amount, percentage     62.00%                            
Financing costs                   1,713,358            
Net income taxes                   4,374 2,762            
Outstanding fair value                              
Smaller Enterprise [Member]                                  
Borrowings [Line Items]                                  
Tangible net 6,000,000                 6,000,000              
Net income taxes                   2,000,000              
Valley Credit Facility [Member]                                  
Borrowings [Line Items]                                  
Outstanding borrowings   32,500,000                              
SBA Debentures [Member]                                  
Borrowings [Line Items]                                  
Outstanding borrowings 203,200,000 160,000,000   $ 170,000,000                          
Interest expense                   1,800,000 1,300,000            
Amortization of deferred financing cost                   200,000 $ 200,000            
Additional long-term capital $ 175,000,000                 $ 175,000,000              
Weighted average interest rate                   3.60% 3.04%            
Debt instrument, interest rate, stated percentage 150.00%                 150.00%              
SBIC [Member]                                  
Borrowings [Line Items]                                  
Tangible net $ 24,000,000                 $ 24,000,000              
Net income taxes                   8,000,000              
7.75% 2025 Notes [Member]                                  
Borrowings [Line Items]                                  
Interest expense                   0 $ 100,000            
Aggregate principal amount                 $ 5,000,000                
Principal amount, percentage                 7.75%                
Net proceeds amount                 $ 4,800,000                
Deducting underwriting commissions amount                 200,000                
Offering costs                 $ 100,000                
Fixed interest, description                 Interest on the 7.75% 2025 Notes was paid quarterly in arrears on February 28, May 31, August 31 and November 30, at a rate of 7.75% per year.                
Deferred financing costs                   0 10,000.00            
Interest expense                   $ 0 5,000,000            
7.75% 2025 Notes [Member] | Fair Value, Inputs, Level 3 [Member]                                  
Borrowings [Line Items]                                  
Outstanding fair value                         $ 14,900,000        
6.25% 2027 Notes [Member]                                  
Borrowings [Line Items]                                  
Outstanding borrowings $ 15,000,000     15,000,000                          
Financing costs               $ 500,000                  
Aggregate principal amount             $ 10,000,000 5,000,000                  
Net proceeds amount             9,700,000                    
Deducting underwriting commissions amount             $ 300,000                    
Offering costs               $ 100,000                  
Fixed interest, description               Interest on the 6.25% 2027 Notes is paid quarterly in arrears on February 28, May 31, August 31 and November 30, at a rate of 6.25% per year.                  
Debt instrument, interest rate, stated percentage 6.25%             6.25%   6.25%              
Par value, per share (in Dollars per share) $ 25                 $ 25              
Outstanding fair value   15,000,000                   15,000,000          
Carrying amount   14,800,000                   14,800,000          
6.25% 2027 Notes [Member] | Borrowings [Member]                                  
Borrowings [Line Items]                                  
Aggregate principal amount               $ 10,000,000                  
Offering costs               $ 100,000                  
Outstanding amount $ 15,000,000                 $ 15,000,000              
6.25% 2027 Notes [Member] | Fair Value, Inputs, Level 3 [Member]                                  
Borrowings [Line Items]                                  
Outstanding borrowings                                
SBIC II LP [Member]                                  
Borrowings [Line Items]                                  
Debentures outstanding amount                   84,000,000              
SBIC III LP [Member]                                  
Borrowings [Line Items]                                  
Debentures outstanding amount                   $ 129,000,000              
SBIC III LP [Member] | SBA Debentures [Member]                                  
Borrowings [Line Items]                                  
Outstanding borrowings $ 213,000,000                                
One Nine Four Zero [Member]                                  
Borrowings [Line Items]                                  
Employ leverage, percentage                   150.00%              
SBIC [Member]                                  
Borrowings [Line Items]                                  
Additional long-term capital                             $ 175,000,000 $ 175,000,000  
Investment percentage 25.00%                 25.00%              
SBIC II LP [Member]                                  
Borrowings [Line Items]                                  
Realized loss on extinguishment of debt                       700,000          
Financing costs                   $ 6,000,000              
Aggregate total of equity capital amount $ 87,500,000                 87,500,000              
SBIC II LP [Member] | SBA Debentures [Member]                                  
Borrowings [Line Items]                                  
Aggregate principal amount                       $ 10,000,000          
SBIC III LP [Member]                                  
Borrowings [Line Items]                                  
Financing costs                   1,400,000              
Aggregate total of equity capital amount 87,500,000                 87,500,000              
SBIC LP [Member]                                  
Borrowings [Line Items]                                  
Financing costs                   $ 5,000,000              
Encina Credit Facility [Member]                                  
Borrowings [Line Items]                                  
Percentage of credit facility           50.00%                      
Credit facility balance, description                   increased the borrowings available under the Encina Credit Facility from up to $50.0 million to up to $65.0 million; (ii) changed the underlying benchmark used to compute interest under the Encina Credit Agreement from LIBOR to Term SOFR for a one-month tenor plus a 0.10% credit spread adjustment; (iii) increased the applicable effective margin rate on borrowings from 4.00% to 4.25%; (iv) extended the revolving period from October 4, 2024 to January 27, 2026; (v) extended the period during which the borrower may request one or more increases in the borrowings available under the Encina Credit Facility (each such increase, a “Facility Increase”) from October 4, 2023 to January 27, 2025, and increased the maximum borrowings available pursuant to the Encina Facility Increase from $75.0 million to $150.0 million; (vi) revised the eligibility criteria for eligible collateral loans to exclude certain industries in which an obligor or related guarantor may be involved; and (vii) amended the provisions permitting the borrower to request an extension in the Commitment Termination Date (as defined in the Encina Credit Agreement) to allow requests to extend any applicable Commitment Termination Date, rather than a one-time request to extend the original Commitment Termination Date, subject to a notice requirement.              
Administrative agent fee                   $ 100,000              
Line of credit facility, borrowing capacity, description                   Availability on the Encina Credit Facility was subject to a borrowing base calculation, based on, among other things, applicable advance rates (which varied from 50.0% to 75.0% of par or fair value depending on the type of loan asset) and the value of certain “eligible” loan assets included as part of the borrowing base. Funds could be borrowed at the greater of the prevailing one-month SOFR rate, plus an applicable effective margin of 4.25%.              
Outstanding borrowings $ 0     $ 32,500,000                          
Realized loss on extinguishment of debt                   $ 100,000              
Interest expense                   $ 0 $ 800,000            
Outstanding percentage rate 0.00%     8.90%           0.00% 8.90%            
Oak Credit Facility [Member]                                  
Borrowings [Line Items]                                  
Line of credit facility maximum borrowing capacity $ 50,000,000                 $ 50,000,000              
Live Oak Credit Facility [Member]                                  
Borrowings [Line Items]                                  
Outstanding borrowings 37,500,000 $ 37,500,000   $ 32,400,000                          
Interest expense                   800,000 $ 800,000            
Amortization of deferred financing cost                   100,000 $ 100,000            
Outstanding percentage rate                           50.00%      
Line of credit facility maximum borrowing capacity                           $ 25,000,000      
Commitment amount                   50,000,000              
Customary fee                   $ 150,000,000              
Line of credit facility minimum drawn amount                           $ 12,500,000      
Percentage of lender         100.00%                        
Credit agreement unused commitment, percentage                   0.50%              
Valley Credit Facility [Member]                                  
Borrowings [Line Items]                                  
Credit facility     $ 25,000,000                            
Percentage of credit facility     38.00%                            
Administrative agent fee                   $ 35,000              
Outstanding borrowings $ 32,500,000                                
Interest expense                   600,000              
Amortization of deferred financing cost                   $ 100,000              
Outstanding percentage rate 6.70%                 6.70%              
Line of credit facility minimum drawn amount $ 85,000,000                 $ 85,000,000              
Floating rate per annum percentage     0.75%             2.85%              
Securitized credit facility     $ 85,000,000                            
Other percentage     0.50%                            
Financing costs                   $ 1,400,000              
Minimum [Member]                                  
Borrowings [Line Items]                                  
Asset coverage ratio                                 150.00%
Credit facility           $ 12,500,000                      
Outstanding amount 350,000,000                                
Minimum [Member] | SBA Debentures [Member]                                  
Borrowings [Line Items]                                  
Leverage limit amount $ 175,000,000                                
Minimum [Member] | Live Oak Credit Facility [Member]                                  
Borrowings [Line Items]                                  
Outstanding percentage rate 7.80%                 7.80%              
Line of credit facility minimum drawn amount         $ 50,000,000                        
Floating rate per annum percentage                   3.50%              
Minimum [Member] | Live Oak Credit Facility Cap [Member]                                  
Borrowings [Line Items]                                  
Line of credit facility minimum drawn amount $ 75,000,000                 $ 75,000,000              
Maximum [Member]                                  
Borrowings [Line Items]                                  
Credit facility           $ 25,000,000                      
Outstanding amount 475,000,000                                
Maximum [Member] | SBA Debentures [Member]                                  
Borrowings [Line Items]                                  
Leverage limit amount 250,000,000                                
Debentures outstanding amount                   $ 213,000,000              
Maximum [Member] | Live Oak Credit Facility [Member]                                  
Borrowings [Line Items]                                  
Outstanding percentage rate       8.50%             8.50%            
Line of credit facility minimum drawn amount         $ 75,000,000                        
Floating rate per annum percentage                   4.25%              
Maximum [Member] | Live Oak Credit Facility Cap [Member]                                  
Borrowings [Line Items]                                  
Line of credit facility minimum drawn amount $ 97,700,000                 $ 97,700,000