Quarterly report pursuant to Section 13 or 15(d)

Related-Party Transactions - Additional Information (Details)

v3.10.0.1
Related-Party Transactions - Additional Information (Details)
$ in Thousands
3 Months Ended 8 Months Ended 9 Months Ended 12 Months Ended
Jan. 10, 2018
Apr. 01, 2017
Mar. 31, 2017
Sep. 30, 2018
USD ($)
Sep. 30, 2017
USD ($)
Jun. 30, 2018
USD ($)
Sep. 30, 2018
USD ($)
officer
Sep. 30, 2017
USD ($)
Dec. 31, 2017
USD ($)
Jun. 11, 2018
Related Party Transaction [Line Items]                    
Number of executive officers that serve as directors | officer             2      
Management fee (as percent)   2.00% 2.00%              
Hurdle rate, quarterly (as percent)   1.75% 1.75%              
Hurdle rate, annual (as percent)   7.00% 7.00%              
Pre-Incentive Fee FFO (as percent)   100.00% 100.00%              
Pre-Incentive Fee, exceeded (as percent)   2.1875% 2.1875%              
Pre-Incentive Fee, exceeded, annual (as percent)   8.75% 8.75%              
Pre-Incentive Fee (as percent)   20.00% 20.00%              
Base management fee, quarterly (as percent)   0.50%                
Cumulative realized capital gains (as percent)   15.00%                
Capital gains fee       $ 778 $ 0   $ 778 $ 0    
Written notice (in days)   120 days                
Credits to fees from adviser       796 54   970 54    
Administration fee       387 211   935 656    
Base management fee       690 523   2,102 1,446    
Gladstone Securities                    
Related Party Transaction [Line Items]                    
Administration fee             $ 57      
Financing fee (as percent)             0.12%      
Taxable REIT Subsidiary                    
Related Party Transaction [Line Items]                    
Professional fees       44   $ 207 $ 136   $ 71  
Allocation of overhead costs       3     31      
Administration fee       18     48      
Base management fee       94     176      
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%                  
Base management fee       $ 890 $ 0   $ 940 $ 0    
Minimum | Gladstone Securities                    
Related Party Transaction [Line Items]                    
Financing fee (as percent)             0.50%      
Maximum | Gladstone Securities                    
Related Party Transaction [Line Items]                    
Financing fee (as percent)             1.00%      
Ventura County California                    
Related Party Transaction [Line Items]                    
Operating lease, term (in years)                   10 years