Annual report pursuant to Section 13 and 15(d)

RELATED PARTY TRANSACTIONS - Narrative (Details)

v3.24.3
RELATED PARTY TRANSACTIONS - Narrative (Details) - USD ($)
 12 Months Ended 24 Months Ended 36 Months Ended
Sep. 30, 2024
Sep. 30, 2023
Mar. 31, 2023
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2020
Sep. 30, 2019
Sep. 30, 2018
Sep. 30, 2017
Sep. 30, 2016
Sep. 30, 2015
Mar. 31, 2022
Mar. 31, 2023
Related Party Transaction [Line Items]                          
Base management fee 1.75% 1.75%   1.75%                  
Base management fee, percent fee 100.00%                        
Investment company, excess expense reimbursable $ 8,000 $ 0   $ 8,000                  
Management and service fee, net of credit 0.50% 0.50%                      
Management and service fees, loans 1.50%                        
Ratio of net investment income (loss) to average net assets – annualized 7.90% 8.49%   6.61% 6.40% 6.11% 6.74% 6.41% 6.13% 6.90% 5.55%    
Incentive fee base on minimum rate of return required on investment $ 0                        
Percentage of pre-incentive fee net investment income is less than the hurdle rate 100.00%                        
Investment company, pre-incentive fee net investment income, percent threshold of net assets 2.1875%   2.50%                 2.4375%  
Pre-incentive fee net investment income exceeds the hurdle rate 20.00%                        
Investment company, capital gains-based incentive fees 20.00%                        
Capital gains-based incentive fee $ 0                        
Investment company, net investment income to common stockholder distributions ratio, threshold   100.00%   100.00%                  
Incentive fee credit 204,000 $ 0   $ 437,000                  
Success fee income 380,000 935,000   4,794,000                  
Investment company, other operating expenses, due to advisor $ 52,000 65,000                      
Gladstone Securities                          
Related Party Transaction [Line Items]                          
Selling commissions, percentage 7.00%                        
Dealer manager fees percentage 3.00%                        
Payments for selling commissions and dealer-manager fees $ 900,000 0                      
Related Party                          
Related Party Transaction [Line Items]                          
Success fee income 400,000 800,000   $ 1,100,000                  
Fees due to related party 4,458,000 4,351,000                      
Related Party | Gladstone Investment Corporation                          
Related Party Transaction [Line Items]                          
Fees due to related party $ 75,000 $ 19,000                      
Total fees due to (from) Adviser | Related Party | Chief Executive Officer                          
Related Party Transaction [Line Items]                          
Noncontrolling interest, ownership percentage by parent 100.00%                        
Fee due to Administrator | Related Party | Chief Executive Officer                          
Related Party Transaction [Line Items]                          
Noncontrolling interest, ownership percentage by parent 100.00%                        
Gladstone Securities, LLC | Related Party | Chief Executive Officer                          
Related Party Transaction [Line Items]                          
Noncontrolling interest, ownership percentage by parent 100.00%                        
Maximum                          
Related Party Transaction [Line Items]                          
Base management fee 1.75%                        
Minimum                          
Related Party Transaction [Line Items]                          
Ratio of net investment income (loss) to average net assets – annualized 1.75%                       2.00%