Annual report pursuant to Section 13 and 15(d)

Equity - Additional Information (Detail)

v3.10.0.1
Equity - Additional Information (Detail)
 1 Months Ended 5 Months Ended 12 Months Ended 21 Months Ended
May 31, 2018
USD ($)
$ / shares
shares
Apr. 12, 2017
USD ($)
security
Dec. 31, 2018
USD ($)
$ / shares
shares
Mar. 31, 2018
USD ($)
$ / shares
shares
May 31, 2018
USD ($)
$ / shares
shares
Dec. 31, 2018
USD ($)
$ / shares
shares
Dec. 31, 2017
USD ($)
$ / shares
shares
Dec. 31, 2018
USD ($)
$ / shares
shares
Jan. 10, 2018
shares
Jan. 09, 2018
shares
Dec. 31, 2016
shares
Aug. 07, 2015
USD ($)
Sale of Stock [Line Items]                        
Stock authorized and unissued (in shares) | shares                 6,500,000      
Common stock, shares authorized (in shares) | shares     91,500,000     91,500,000 98,000,000 91,500,000 91,500,000 98,000,000    
Preferred stock, liquidation value | $     $ 28,600,000     $ 28,600,000   $ 28,600,000        
Common stock, par value (in dollars per share) | $ / shares     $ 0.001     $ 0.001 $ 0.001 $ 0.001        
Common stock, shares issued (in shares) | shares     17,891,340     17,891,340 13,791,574 17,891,340        
Common stock, shares outstanding (in shares) | shares     17,891,340     17,891,340 13,791,574 17,891,340        
Maximum number of securities that can be sold (in securities) | security   2                    
Proceeds from issuance of preferred and common equity | $           $ 74,417,000 $ 41,907,000          
Payments of stock issuance costs | $           $ 4,186,000 $ 1,977,000          
2017 Registration Statement                        
Sale of Stock [Line Items]                        
Proceeds from issuance of preferred and common equity | $               $ 67,500,000        
Secondary Public Stock Offering                        
Sale of Stock [Line Items]                        
Sale of common stock sold under sale agreement (in shares) | shares     1,450,000 1,265,000                
Average sales price of common stock sold (in dollars per share) | $ / shares     $ 12.55 $ 12.15   $ 12.55   $ 12.55        
Proceeds from issuance of stock | $     $ 18,200,000 $ 15,400,000                
Net proceeds from issuance of common stock | $       $ 14,600,000                
Payments of stock issuance costs | $     $ 17,300,000                  
ATM Program                        
Sale of Stock [Line Items]                        
Common stock, shares issued (in shares) | shares     1,595,591     1,595,591   1,595,591        
Sale of common stock sold under sale agreement (in shares) | shares           986,955            
Common stock, value authorized | $                       $ 30,000,000.0
Average sales price (in dollars per share) | $ / shares     $ 12.87     $ 12.87   $ 12.87        
Common stock, value, outstanding | $     $ 20,500,000     $ 20,500,000   $ 20,500,000        
Common stock, value, issued | $     $ 20,200,000     20,200,000   $ 20,200,000        
At Market Program 2017 Issuances                        
Sale of Stock [Line Items]                        
Proceeds from issuance of stock | $           12,800,000            
Payments of stock issuance costs | $           $ 12,600,000            
Average sales price (in dollars per share) | $ / shares     $ 12.95     $ 12.95   $ 12.95        
Common Stock | 2017 Registration Statement                        
Sale of Stock [Line Items]                        
Common stock, shares issued (in shares) | shares     5,396,030     5,396,030   5,396,030        
Securities allowed for issuance (amount up to) | $   $ 300,000,000                    
Common stock, issued (in shares) | shares               644,686.000        
Gladstone Land Limited Partnership                        
Sale of Stock [Line Items]                        
OP units held by non-controlling limited partners (in shares) | shares           570,879 1,008,105          
OP units held by non-controlling interest limited partners (in shares) | shares     570,879     570,879   570,879        
Series B Preferred Stock                        
Sale of Stock [Line Items]                        
Preferred stock, shares authorized (in shares) | shares     6,500,000     6,500,000 0 6,500,000        
Preferred stock, par value (in dollars per share) | $ / shares     $ 0.001     $ 0.001 $ 0 $ 0.001        
Preferred stock, shares issued (in shares) | shares     1,144,393     1,144,393 0 1,144,393        
Preferred stock, shares outstanding (in shares) | shares     1,144,393     1,144,393 0 1,144,393        
Series B Preferred Stock | Preferred Stock                        
Sale of Stock [Line Items]                        
Preferred stock, shares outstanding (in shares) | shares     1,144,393     1,144,393 0 1,144,393     0  
Securities allowed for issuance (amount up to) | $ $ 150,000,000       $ 150,000,000              
Sale of common stock sold under sale agreement (in shares) | shares         0 1,144,393            
Proceeds from issuance and preferred stock | $ $ 131,300,000         $ 28,100,000            
Preferred stock, dividend rate (as percent) 6.00%                      
Maximum amount authorized in Primary Offering (in shares) | shares 6,000,000                      
Average sales price of common stock sold (in dollars per share) | $ / shares $ 25       $ 25              
Proceeds from issuance of stock | $           25,700,000            
Payments of stock issuance costs | $           $ 766,000            
OP Unit Holder                        
Sale of Stock [Line Items]                        
Minimum period required to exercise, in months           12 months