Annual report pursuant to Section 13 and 15(d)

Equity - Additional Information (Detail)

v3.6.0.2
Equity - Additional Information (Detail) - USD ($)
 12 Months Ended
Aug. 17, 2016
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Aug. 07, 2015
Apr. 02, 2014
Dec. 31, 2013
Subsidiary, Sale of Stock [Line Items]              
Common stock, shares authorized (in shares)   18,000,000 20,000,000        
Common stock, par value (in dollars per share)   $ 0.001 $ 0.001        
Common stock, shares issued (in shares)   10,024,875 9,992,941        
Common stock, shares outstanding (in shares)   10,024,875 9,992,941        
Operating partnership units held by anyone other than Company (in shares)     0 0      
Payments of dividends   $ 5,000,000 $ 4,100,000 $ 2,500,000      
Securities allowed for issuance           $ 300,000,000  
Proceeds from issuance of mandatorily-redeemable preferred stock   $ 28,750,000 $ 0 $ 0      
Common Stock              
Subsidiary, Sale of Stock [Line Items]              
Common stock, shares outstanding (in shares)   10,024,875 9,992,941 7,753,717     6,530,264
Value of common stock issuable per registration statement   $ 23,600,000          
Number of shares issued (in shares)   31,934 2,239,224 1,223,453      
Universal Registration Statement | Common Stock              
Subsidiary, Sale of Stock [Line Items]              
Common stock, shares issued (in shares)   2,188,014          
At-the-Market Program              
Subsidiary, Sale of Stock [Line Items]              
Common stock, shares issued (in shares)   64,561          
Common stock, value authorized         $ 30,000,000.0    
Sale of common stock sold under sale agreement (in shares)   31,934          
Average sales price of common stock sold (in dollars per share)   $ 11.29          
Gross proceeds from issuance of common stock   $ 360,000          
Net proceeds from issuance of common stock   $ 355,000          
Average sales price (in dollars per share)   $ 10.23          
Gross proceeds from shares issued   $ 660,000          
Net proceeds from shares issued   $ 650,000          
Series A cumulative term preferred stock              
Subsidiary, Sale of Stock [Line Items]              
Number of shares issued (in shares) 1,000,000 1,150,000          
Average sales price (in dollars per share) $ 25            
Gladstone Land Limited Partnership              
Subsidiary, Sale of Stock [Line Items]              
Company's ownership percent of voting securities of Land Advisers   87.40% 100.00%        
Operating partnership units held by anyone other than Company (in shares)   1,449,258