Quarterly report pursuant to Section 13 or 15(d)

Real Estate and Intangible Assets - Fair Value of Acquired Assets and Liabilities Assumed Related to Properties Acquired (Detail)

v2.4.1.9
Real Estate and Intangible Assets - Fair Value of Acquired Assets and Liabilities Assumed Related to Properties Acquired (Detail) (2015 New Real Estate Activity [Member], USD $)
Mar. 31, 2015
Business Acquisition Purchase Price Allocation [Line Items]  
Total Acquisition Cost $ 20,821,405us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet
In-place Leases [Member]
 
Business Acquisition Purchase Price Allocation [Line Items]  
Total Acquisition Cost 300,877us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet
/ us-gaap_MajorPropertyClassAxis
= land_InPlaceLeasesMember
/ us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis
= land_TwoThousandFifteenNewRealEstateActivityMember
Espinosa Road [Member]
 
Business Acquisition Purchase Price Allocation [Line Items]  
Total Acquisition Cost 16,906,125us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet
/ us-gaap_RealEstatePropertiesAxis
= land_EspinosaRoadMember
/ us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis
= land_TwoThousandFifteenNewRealEstateActivityMember
Espinosa Road [Member] | In-place Leases [Member]
 
Business Acquisition Purchase Price Allocation [Line Items]  
Total Acquisition Cost 246,472us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet
/ us-gaap_MajorPropertyClassAxis
= land_InPlaceLeasesMember
/ us-gaap_RealEstatePropertiesAxis
= land_EspinosaRoadMember
/ us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis
= land_TwoThousandFifteenNewRealEstateActivityMember
Parrish Road [Member]
 
Business Acquisition Purchase Price Allocation [Line Items]  
Total Acquisition Cost 3,915,280us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet
/ us-gaap_RealEstatePropertiesAxis
= land_ParrishRoadMember
/ us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis
= land_TwoThousandFifteenNewRealEstateActivityMember
Parrish Road [Member] | In-place Leases [Member]
 
Business Acquisition Purchase Price Allocation [Line Items]  
Total Acquisition Cost 54,405us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet
/ us-gaap_MajorPropertyClassAxis
= land_InPlaceLeasesMember
/ us-gaap_RealEstatePropertiesAxis
= land_ParrishRoadMember
/ us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis
= land_TwoThousandFifteenNewRealEstateActivityMember
Irrigation System [Member]
 
Business Acquisition Purchase Price Allocation [Line Items]  
Total Acquisition Cost 1,797,252us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_IrrigationSystemMember
/ us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis
= land_TwoThousandFifteenNewRealEstateActivityMember
Irrigation System [Member] | Espinosa Road [Member]
 
Business Acquisition Purchase Price Allocation [Line Items]  
Total Acquisition Cost 497,401us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_IrrigationSystemMember
/ us-gaap_RealEstatePropertiesAxis
= land_EspinosaRoadMember
/ us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis
= land_TwoThousandFifteenNewRealEstateActivityMember
Irrigation System [Member] | Parrish Road [Member]
 
Business Acquisition Purchase Price Allocation [Line Items]  
Total Acquisition Cost 1,299,851us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_IrrigationSystemMember
/ us-gaap_RealEstatePropertiesAxis
= land_ParrishRoadMember
/ us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis
= land_TwoThousandFifteenNewRealEstateActivityMember
Leasing Costs [Member]
 
Business Acquisition Purchase Price Allocation [Line Items]  
Total Acquisition Cost 123,968us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_LeasingCostsMember
/ us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis
= land_TwoThousandFifteenNewRealEstateActivityMember
Leasing Costs [Member] | Espinosa Road [Member]
 
Business Acquisition Purchase Price Allocation [Line Items]  
Total Acquisition Cost 44,519us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_LeasingCostsMember
/ us-gaap_RealEstatePropertiesAxis
= land_EspinosaRoadMember
/ us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis
= land_TwoThousandFifteenNewRealEstateActivityMember
Leasing Costs [Member] | Parrish Road [Member]
 
Business Acquisition Purchase Price Allocation [Line Items]  
Total Acquisition Cost 79,449us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_LeasingCostsMember
/ us-gaap_RealEstatePropertiesAxis
= land_ParrishRoadMember
/ us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis
= land_TwoThousandFifteenNewRealEstateActivityMember
Customer Relationships [Member]
 
Business Acquisition Purchase Price Allocation [Line Items]  
Total Acquisition Cost 216,681us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_CustomerRelationshipsMember
/ us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis
= land_TwoThousandFifteenNewRealEstateActivityMember
Customer Relationships [Member] | Espinosa Road [Member]
 
Business Acquisition Purchase Price Allocation [Line Items]  
Total Acquisition Cost 180,789us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_CustomerRelationshipsMember
/ us-gaap_RealEstatePropertiesAxis
= land_EspinosaRoadMember
/ us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis
= land_TwoThousandFifteenNewRealEstateActivityMember
Customer Relationships [Member] | Parrish Road [Member]
 
Business Acquisition Purchase Price Allocation [Line Items]  
Total Acquisition Cost 35,892us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_CustomerRelationshipsMember
/ us-gaap_RealEstatePropertiesAxis
= land_ParrishRoadMember
/ us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis
= land_TwoThousandFifteenNewRealEstateActivityMember
Land and Land Improvements [Member]  
Business Acquisition Purchase Price Allocation [Line Items]  
Total Acquisition Cost 18,255,530us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_LandAndLandImprovementsMember
/ us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis
= land_TwoThousandFifteenNewRealEstateActivityMember
Land and Land Improvements [Member] | Espinosa Road [Member]  
Business Acquisition Purchase Price Allocation [Line Items]  
Total Acquisition Cost 15,852,466us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_LandAndLandImprovementsMember
/ us-gaap_RealEstatePropertiesAxis
= land_EspinosaRoadMember
/ us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis
= land_TwoThousandFifteenNewRealEstateActivityMember
Land and Land Improvements [Member] | Parrish Road [Member]  
Business Acquisition Purchase Price Allocation [Line Items]  
Total Acquisition Cost 2,403,064us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_LandAndLandImprovementsMember
/ us-gaap_RealEstatePropertiesAxis
= land_ParrishRoadMember
/ us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis
= land_TwoThousandFifteenNewRealEstateActivityMember
Buildings and Improvements [Member]  
Business Acquisition Purchase Price Allocation [Line Items]  
Total Acquisition Cost 127,097us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_BuildingAndBuildingImprovementsMember
/ us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis
= land_TwoThousandFifteenNewRealEstateActivityMember
Buildings and Improvements [Member] | Espinosa Road [Member]  
Business Acquisition Purchase Price Allocation [Line Items]  
Total Acquisition Cost 84,478us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_BuildingAndBuildingImprovementsMember
/ us-gaap_RealEstatePropertiesAxis
= land_EspinosaRoadMember
/ us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis
= land_TwoThousandFifteenNewRealEstateActivityMember
Buildings and Improvements [Member] | Parrish Road [Member]  
Business Acquisition Purchase Price Allocation [Line Items]  
Total Acquisition Cost $ 42,619us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_BuildingAndBuildingImprovementsMember
/ us-gaap_RealEstatePropertiesAxis
= land_ParrishRoadMember
/ us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis
= land_TwoThousandFifteenNewRealEstateActivityMember