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