Annual report pursuant to Section 13 and 15(d)

Related-Party Transactions - Additional Information (Detail)

v3.20.4
Related-Party Transactions - Additional Information (Detail)
$ in Thousands
 12 Months Ended
Feb. 20, 2020
Jan. 10, 2018
Dec. 31, 2020
USD ($)
officer
Dec. 31, 2019
USD ($)
Related Party Transaction [Line Items]        
Number of executive officers that serve as directors | officer     2  
Hurdle rate, quarterly (as percent)     1.75%  
Hurdle rate, annual (as percent)     7.00%  
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%  
Written notice (in days)     120 days  
Financing fee     $ 262 $ 235
Dealer-manager fees     $ 4,711 7,645
Prior Advisory Agreement        
Related Party Transaction [Line Items]        
Management fee (as percent)     2.00%  
Base management fee, quarterly (as percent)     0.50%  
2019 Advisory Agreement        
Related Party Transaction [Line Items]        
Management fee (as percent)     2.00%  
Base management fee, quarterly (as percent)     0.50%  
2020 Advisory Agreement        
Related Party Transaction [Line Items]        
Management fee (as percent)     2.00%  
Base management fee, quarterly (as percent)     0.50%  
Gladstone Securities        
Related Party Transaction [Line Items]        
Financing fee (as percent)     0.14%  
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 B Preferred Stock | Gladstone Securities        
Related Party Transaction [Line Items]        
Dealer-manager fees     $ 2,500 $ 7,600
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%      
Dealer-manager fees     $ 2,200  
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%