Quarterly report pursuant to Section 13 or 15(d)

Related-Party Transactions (Details)

v3.23.3
Related-Party Transactions (Details)
 3 Months Ended 9 Months Ended
Jul. 11, 2023
Jul. 14, 2020
Feb. 20, 2020
$ / shares
shares
Sep. 30, 2023
USD ($)
Sep. 30, 2022
USD ($)
Sep. 30, 2023
USD ($)
officer
quarter
Sep. 30, 2022
USD ($)
Dec. 31, 2022
USD ($)
Related Party Transaction [Line Items]                
Number of executive officers | officer           2    
Related Party                
Related Party Transaction [Line Items]                
Amount due to advisor and administrator [1]       $ 2,552,000   $ 2,552,000   $ 3,356,000
Advisory Agreement                
Related Party Transaction [Line Items]                
Number of quarters used for the cap of average quarterly incentive fees | quarter           4    
Advisory Agreement | Affiliated Entity                
Related Party Transaction [Line Items]                
Notice period for termination of agreement without cause           120 days    
Percentage of independent directors required to terminate the amended advisory agreement           66.67%    
Number of times the sum of the average annual base management fee and incentive fee earned by adviser       2   2    
Period prior to termination           24 months    
Notice period for termination of agreement with cause           30 days    
Advisory Agreement - Base Rate, Annualized Rate | Affiliated Entity                
Related Party Transaction [Line Items]                
Management and service fees, base rate   0.425%            
Advisory Agreement - Base Rate, Quarterly Rate | Affiliated Entity                
Related Party Transaction [Line Items]                
Management and service fees, base rate   0.10625%            
Advisory Agreement - Base Management Fee                
Related Party Transaction [Line Items]                
Related party transaction, amounts of transaction       $ 1,600,000 $ 1,600,000 $ 4,800,000 $ 4,700,000  
Advisory Agreement - Incentive Rate, Quarterly Hurdle Rate | Affiliated Entity                
Related Party Transaction [Line Items]                
Management and service fees, incentive rate           2.00%    
Advisory Agreement - Incentive Rate, Annualized Hurdle Rate | Affiliated Entity                
Related Party Transaction [Line Items]                
Management and service fees, incentive rate           8.00%    
Advisory Agreement - Incentive Rate, Pre-Incentive Fee Net Investment Income Below Catch-Up Threshold | Affiliated Entity                
Related Party Transaction [Line Items]                
Management and service fees, incentive rate           15.00%    
Advisory Agreement - Incentive Rate, Pre-Incentive Fee Net Investment Income Exceeds Catch-Up Threshold | Affiliated Entity                
Related Party Transaction [Line Items]                
Management and service fees, incentive rate           15.00%    
Eight Amended Advisory Agreement | Affiliated Entity                
Related Party Transaction [Line Items]                
Management and service fees, incentive rate 15.00%              
Advisory Agreement - Incentive Fees | Affiliated Entity                
Related Party Transaction [Line Items]                
Related party transaction, amounts of transaction         1,500,000   4,200,000  
Contractual fee waived       900,000   $ 3,400,000    
Investment company, voluntary fee waived         0   0  
Advisory Agreement - Incentive Rate, Realized Capital Gains                
Related Party Transaction [Line Items]                
Related party transaction, amounts of transaction       0 0 $ 0 0  
Advisory Agreement - Incentive Rate, Realized Capital Gains | Affiliated Entity                
Related Party Transaction [Line Items]                
Management and service fees, incentive rate           15.00%    
Advisory Agreement - Termination Fee Payable as a Percentage of Management and Incentive Fees Earned by Adviser | Affiliated Entity                
Related Party Transaction [Line Items]                
Related party transaction, rate           200.00%    
Administrative Agreement - Administrative Fee                
Related Party Transaction [Line Items]                
Related party transaction, amounts of transaction       600,000 500,000 $ 1,700,000 1,300,000  
Mortgage Financing Arrangement Agreement - Financing Fees | Gladstone Securities, LLC                
Related Party Transaction [Line Items]                
Related party transaction, amounts of transaction       $ 30,000.00 $ 100,000 $ 100,000 $ 300,000  
Mortgage Financing Arrangement Agreement - Percentage of Mortgage Principal Secured | Gladstone Securities, LLC                
Related Party Transaction [Line Items]                
Related party transaction, rate       0.38% 0.29% 0.29% 0.32%  
Dealer Manager Agreement | Gladstone Securities, LLC                
Related Party Transaction [Line Items]                
Related party transaction, amounts of transaction       $ 100,000 $ 100,000 $ 500,000 $ 400,000  
Dealer Manager Agreement - Selling Commission Percentage of Gross Proceeds From Sales                
Related Party Transaction [Line Items]                
Related party transaction, rate     6.00%          
Dealer Manager Agreement - Dealer Management Fee Percentage of Gross Proceeds from Sale of Preferred Stock in Primary Offering                
Related Party Transaction [Line Items]                
Related party transaction, rate     3.00%          
Series F Cumulative Redeemable Preferred Stock | Preferred Stock | Dealer Manager Agreement | Affiliated Entity | Gladstone Securities, LLC                
Related Party Transaction [Line Items]                
Redeemable preferred stock, shares authorized (in shares) | shares     20,000,000          
Redeemable preferred stock, dividend rate     6.00%          
Redeemable preferred stock, par value (in dollars per share) | $ / shares     $ 0.001          
Redeemable preferred stock, dividend reinvestment plan, shares authorized (in shares) | shares     6,000,000          
Minimum | Mortgage Financing Arrangement Agreement - Financing Fees | Gladstone Securities, LLC                
Related Party Transaction [Line Items]                
Related party transaction, rate           0.15%    
Maximum | Mortgage Financing Arrangement Agreement - Financing Fees | Gladstone Securities, LLC                
Related Party Transaction [Line Items]                
Related party transaction, rate           1.00%    
[1] Refer to Note 2 “Related-Party Transactions”