Annual report pursuant to Section 13 and 15(d)

Related-Party Transactions - Additional Information (Detail)

v3.10.0.1
Related-Party Transactions - Additional Information (Detail)
 3 Months Ended 8 Months Ended 12 Months Ended
Jan. 10, 2018
Apr. 01, 2017
Dec. 31, 2018
USD ($)
a
Jun. 30, 2018
USD ($)
Dec. 31, 2018
USD ($)
a
officer
Dec. 31, 2017
USD ($)
a
Jun. 11, 2018
a
Oct. 17, 2017
USD ($)
a
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%            
Base management fee, waiver credit granted by Adviser         $ 46,000      
Cumulative realized capital gains (as percent)   15.00%            
Capital gains fee         628,000 $ 0    
Capital gains fee, waiver credit granted by Adviser         $ 778,000      
Capital gains fee, reduction of fee due to capital losses     $ 150,000          
Written notice (in days)   120 days            
Total Acres | a     73,205   73,205 63,014    
Base management fee         $ 2,837,000 $ 2,041,000    
Crop inventory     $ 0.0   0.0 1,528,000    
Administration fee         1,275,000 914,000    
Financing fee         83,000 36,000    
Payment of management fees           0    
Gladstone Securities                
Related Party Transaction [Line Items]                
Payment of management fees         $ 2,200,000      
Unsecured Debt | Land Advisers                
Related Party Transaction [Line Items]                
Debt instrument, face amount               $ 1,700,000
Interest rate (as percent)               5.00%
Affiliate                
Related Party Transaction [Line Items]                
Financing fee (as percent)         0.12%      
Taxable REIT Subsidiary                
Related Party Transaction [Line Items]                
Professional fees       $ 207,000 $ 136,000 71,000    
Base management fee         176,000      
Allocation of overhead costs         31,000      
Fee waiver granted         190,000      
Administration fee         57,000 $ 22,000    
Taxable REIT Subsidiary | Land Advisers                
Related Party Transaction [Line Items]                
Base management fee         176,000      
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%              
Payment of management fees         $ 2,324,000      
Ventura County, California                
Related Party Transaction [Line Items]                
Total Acres | a             169 169
Operating lease, term (in years)             10 years  
Gladstone Securities | Minimum | Affiliate                
Related Party Transaction [Line Items]                
Financing fee (as percent)         0.50%      
Gladstone Securities | Maximum | Affiliate                
Related Party Transaction [Line Items]                
Financing fee (as percent)         1.00%