Quarterly report pursuant to Section 13 or 15(d)

RELATED PARTY TRANSACTIONS - Narrative (Details)

v3.23.1
RELATED PARTY TRANSACTIONS - Narrative (Details) - USD ($)
 3 Months Ended 6 Months Ended 12 Months Ended 24 Months Ended 36 Months Ended
Apr. 11, 2022
Mar. 31, 2023
Mar. 31, 2022
Mar. 31, 2023
Mar. 31, 2022
Mar. 31, 2023
Mar. 31, 2023
Apr. 11, 2022
Mar. 31, 2022
Mar. 31, 2023
Sep. 30, 2022
Related Party Transaction [Line Items]                      
Base management fee       1.75% 1.75%            
Base management fee, percent fee       100.00%              
Management and service fee, net of credit   0.50% 0.50% 0.50% 0.50%            
Management and service fees, loans       1.50%              
Ratio of net investment income (loss) to average net assets – annualized 2.1875% 8.30% 8.72% 8.09% 7.98%   2.50% 2.4375%      
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, investment income (loss) ratio, before incentive allocation, annualized 8.75%           10.00% 9.75%      
Investment company, capital gains-based incentive fees   20.00%   20.00%   20.00% 20.00%     20.00%  
Success fee income   $ 600,000 $ 3,231,000 $ 600,000 $ 4,794,000            
Investment company, other operating expenses, due to advisor   100,000   100,000   $ 100,000 $ 100,000     $ 100,000 $ 44,000
Fees due to related party   3,762,000   3,762,000   3,762,000 3,762,000     3,762,000 2,527,000
Gladstone Investment Corporation                      
Related Party Transaction [Line Items]                      
Fees due to related party   0   0   $ 0 $ 0     $ 0 $ 13,000
Affiliated Entity                      
Related Party Transaction [Line Items]                      
Success fee income   $ 200,000 $ 25,000 $ 300,000 $ 600,000            
Adviser | David Gladstone | Chief Executive Officer                      
Related Party Transaction [Line Items]                      
Noncontrolling interest, ownership percentage by parent   100.00%   100.00%   100.00% 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%   100.00% 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%   100.00% 100.00%     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%