Quarterly report pursuant to Section 13 or 15(d)

Real Estate and Intangible Assets - Carrying Value of Lease Intangibles and Accumulated Amortization for Each Intangible Asset or Liability Class (Detail)

v2.4.1.9
Real Estate and Intangible Assets - Carrying Value of Lease Intangibles and Accumulated Amortization for Each Intangible Asset or Liability Class (Detail) (USD $)
Mar. 31, 2015
Dec. 31, 2014
Mar. 31, 2014
Finite-Lived Intangible Assets [Line Items]      
Below-market lease values, gross $ (371,707)us-gaap_BelowMarketLeaseGross $ (371,707)us-gaap_BelowMarketLeaseGross  
Below-market lease values, accumulated (amortization) accretion 217,337us-gaap_BelowMarketLeaseAccumulatedAmortization 162,194us-gaap_BelowMarketLeaseAccumulatedAmortization 162,194us-gaap_BelowMarketLeaseAccumulatedAmortization
Above-Market Lease Values [Member]      
Finite-Lived Intangible Assets [Line Items]      
Finite-lived intangible assets, gross 65,203us-gaap_FiniteLivedIntangibleAssetsGross
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_AboveMarketLeasesMember
65,203us-gaap_FiniteLivedIntangibleAssetsGross
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_AboveMarketLeasesMember
 
Finite-lived intangible asset, accumulated (amortization) accretion (14,422)us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_AboveMarketLeasesMember
(9,027)us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_AboveMarketLeasesMember
 
Above (Below)-Market Leases [Member]      
Finite-Lived Intangible Assets [Line Items]      
Finite-lived intangible assets, gross (306,504)us-gaap_FiniteLivedIntangibleAssetsGross
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_AboveAndBelowMarketLeasesMember
(306,504)us-gaap_FiniteLivedIntangibleAssetsGross
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_AboveAndBelowMarketLeasesMember
 
Finite-lived intangible asset, accumulated (amortization) accretion 202,915us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_AboveAndBelowMarketLeasesMember
153,167us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_AboveAndBelowMarketLeasesMember
 
In-place Leases [Member]      
Finite-Lived Intangible Assets [Line Items]      
Finite-lived intangible assets, gross 1,170,083us-gaap_FiniteLivedIntangibleAssetsGross
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_InPlaceLeasesMember
869,207us-gaap_FiniteLivedIntangibleAssetsGross
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_InPlaceLeasesMember
 
Finite-lived intangible asset, accumulated (amortization) accretion (448,741)us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_InPlaceLeasesMember
(263,428)us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_InPlaceLeasesMember
 
Leasing Commissions [Member]      
Finite-Lived Intangible Assets [Line Items]      
Finite-lived intangible assets, gross 480,790us-gaap_FiniteLivedIntangibleAssetsGross
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_LeasingCommissionsMember
357,210us-gaap_FiniteLivedIntangibleAssetsGross
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_LeasingCommissionsMember
 
Finite-lived intangible asset, accumulated (amortization) accretion (116,619)us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_LeasingCommissionsMember
(80,617)us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_LeasingCommissionsMember
 
Tenant Relationships [Member]      
Finite-Lived Intangible Assets [Line Items]      
Finite-lived intangible assets, gross 718,351us-gaap_FiniteLivedIntangibleAssetsGross
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_TenantRelationshipsMember
501,670us-gaap_FiniteLivedIntangibleAssetsGross
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_TenantRelationshipsMember
 
Finite-lived intangible asset, accumulated (amortization) accretion (124,270)us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_TenantRelationshipsMember
(66,467)us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_TenantRelationshipsMember
 
Lease Intangibles [Member]      
Finite-Lived Intangible Assets [Line Items]      
Finite-lived intangible assets, gross 2,369,224us-gaap_FiniteLivedIntangibleAssetsGross
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_LeaseIntangiblesMember
1,728,087us-gaap_FiniteLivedIntangibleAssetsGross
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_LeaseIntangiblesMember
 
Finite-lived intangible asset, accumulated (amortization) accretion $ (689,630)us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_LeaseIntangiblesMember
$ (410,512)us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_LeaseIntangiblesMember