Annual report pursuant to Section 13 and 15(d)

Real Estate and Lease Intangibles - Schedule of Purchase Agreements (Parenthetical) (Detail)

v2.4.1.9
Real Estate and Lease Intangibles - Schedule of Purchase Agreements (Parenthetical) (Detail) (Strawberries [Member], California [Member], USD $)
 12 Months Ended
Dec. 31, 2014
2014 Agreement [Member]  
Real Estate Properties [Line Items]  
Agreement termination date Jan. 20, 2015
Deposits included in other assets $ 100,000us-gaap_DepositsAssetsCurrent
/ invest_InvestmentAxis
= land_TwoThousandFourteenAgreementMember
/ us-gaap_RealEstatePropertiesAxis
= land_StrawberriesMember
/ us-gaap_StatementGeographicalAxis
= stpr_CA
2015 Agreement [Member]  
Real Estate Properties [Line Items]  
Acquisition date Jan. 05, 2015