Quarterly report pursuant to Section 13 or 15(d)

Related-Party Transactions - Additional Information (Details)

v3.20.1
Related-Party Transactions - Additional Information (Details)
$ in Thousands
 3 Months Ended
Jan. 10, 2018
Apr. 01, 2017
Mar. 31, 2020
USD ($)
officer
Mar. 31, 2019
USD ($)
Related Party Transaction [Line Items]        
Number of executive officers that serve as directors | officer     2  
Pre-Incentive Fee FFO (as percent)     100.00%  
Pre-Incentive Fee, exceeded (as percent)     2.1875%  
Pre-Incentive Fee, exceeded, annual (as percent)     8.75%  
Pre-Incentive Fee (as percent)     20.00%  
Cumulative realized capital gains (as percent)     15.00%  
Notice period for termination of agreement without cause   120 days    
Administration fee     $ 0 $ 2
Selling commissions and dealer-manager fees     $ 2,484 1,654
Prior Advisory Agreement        
Related Party Transaction [Line Items]        
Management fee (as percent)     2.00%  
Base management fee, quarterly (as percent)     0.50%  
Hurdle rate, quarterly (as percent)     1.75%  
Hurdle rate, annual (as percent)     7.00%  
2020 Advisory Agreement        
Related Party Transaction [Line Items]        
Management fee (as percent)     0.50%  
Base management fee, quarterly (as percent)     0.125%  
Hurdle rate, quarterly (as percent)     1.75%  
Hurdle rate, annual (as percent)     7.00%  
Gladstone Securities        
Related Party Transaction [Line Items]        
Financing fee (as percent)     0.13%  
Administration fee     $ 0 2
Preferred Stock | Series B Preferred Stock        
Related Party Transaction [Line Items]        
Selling commission fee (as percent) 7.00%      
Dealer-manager fee (as percent) 3.00%      
Preferred Stock | Series C Preferred Stock        
Related Party Transaction [Line Items]        
Selling commission fee (as percent) 6.00%      
Dealer-manager fee (as percent) 3.00%      
Gladstone Securities | Preferred Stock | Series B Preferred Stock        
Related Party Transaction [Line Items]        
Selling commissions and dealer-manager fees     $ 2,500 $ 1,654
Gladstone Securities | Minimum | Gladstone Securities        
Related Party Transaction [Line Items]        
Financing fee (as percent)     0.50%  
Gladstone Securities | Maximum | Gladstone Securities        
Related Party Transaction [Line Items]        
Financing fee (as percent)     1.00%