Quarterly report pursuant to Section 13 or 15(d)

RELATED PARTY TRANSACTIONS - Narrative (Details)

v3.22.2.2
RELATED PARTY TRANSACTIONS - Narrative (Details) - USD ($)
3 Months Ended 6 Months Ended 12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2022
Sep. 30, 2021
Mar. 31, 2022
Related Party Transaction [Line Items]          
Base management fee 2.00% 2.00% 2.00% 2.00%  
Base management fee, percent fee     100.00%    
Investment company, excess expense reimbursable $ 70,000 $ 132,000 $ 106,000 $ 63,000  
Maximum base management fee paid cannot exceed a percentage of total assets     2.00%    
Ratio of net investment income (loss) to average net assets – annualized 7.01% (0.52%) 5.69% (2.91%)  
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%    
Pre-incentive fee net investment income exceeds the hurdle rate     20.00%    
Investment company, capital gains-based incentive fees 20.00%   20.00%    
Investment company, capital gains-based incentive fees     $ 0   $ 5,300,000
Investment company, capital gains-based incentive fees payable $ (1,700,000) $ 5,600,000 (700,000) $ 15,900,000  
Success fee income 1,733,000 2,650,000 6,733,000 4,682,000  
Due from related parties 13,000   $ 13,000   $ 27,000
Minimum          
Related Party Transaction [Line Items]          
Ratio of net investment income (loss) to average net assets – annualized     1.75%    
Affiliated Entity          
Related Party Transaction [Line Items]          
Success fee income $ 1,000,000 $ 300,000 $ 1,300,000 $ 400,000  
Adviser | David Gladstone | Chief Executive Officer          
Related Party Transaction [Line Items]          
Noncontrolling interest, ownership percentage by parent 100.00%   100.00%    
Administrator | David Gladstone | Chief Executive Officer          
Related Party Transaction [Line Items]          
Noncontrolling interest, ownership percentage by parent 100.00%   100.00%    
Gladstone Securities, LLC | David Gladstone | Chief Executive Officer          
Related Party Transaction [Line Items]          
Noncontrolling interest, ownership percentage by parent 100.00%   100.00%