Annual report pursuant to Section 13 and 15(d)

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

v2.4.1.9
Real Estate and Lease Intangibles - Carrying Value of Lease Intangibles and Accumulated Amortization for Each Intangible Asset or Liability Class (Detail) (USD $)
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Finite-Lived Intangible Assets [Line Items]      
Below-market lease values, gross $ (371,707)us-gaap_BelowMarketLeaseGross $ (260,356)us-gaap_BelowMarketLeaseGross  
Below-market lease values, accumulated (amortization) accretion 162,194us-gaap_BelowMarketLeaseAccumulatedAmortization 114,469us-gaap_BelowMarketLeaseAccumulatedAmortization 45,852us-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
   
Finite-lived intangible asset, accumulated (amortization) accretion (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
(260,356)us-gaap_FiniteLivedIntangibleAssetsGross
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_AboveAndBelowMarketLeasesMember
 
Finite-lived intangible asset, accumulated (amortization) accretion 153,167us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_AboveAndBelowMarketLeasesMember
114,469us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_AboveAndBelowMarketLeasesMember
 
In-place Leases [Member]      
Finite-Lived Intangible Assets [Line Items]      
Finite-lived intangible assets, gross 869,207us-gaap_FiniteLivedIntangibleAssetsGross
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_InPlaceLeasesMember
397,728us-gaap_FiniteLivedIntangibleAssetsGross
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_InPlaceLeasesMember
 
Finite-lived intangible asset, accumulated (amortization) accretion (263,428)us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_InPlaceLeasesMember
(241,697)us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_InPlaceLeasesMember
 
Leasing Commissions [Member]      
Finite-Lived Intangible Assets [Line Items]      
Finite-lived intangible assets, gross 357,210us-gaap_FiniteLivedIntangibleAssetsGross
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_LeasingCommissionsMember
146,558us-gaap_FiniteLivedIntangibleAssetsGross
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_LeasingCommissionsMember
 
Finite-lived intangible asset, accumulated (amortization) accretion (80,617)us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_LeasingCommissionsMember
(34,727)us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_LeasingCommissionsMember
 
Tenant Relationships [Member]      
Finite-Lived Intangible Assets [Line Items]      
Finite-lived intangible assets, gross 501,670us-gaap_FiniteLivedIntangibleAssetsGross
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_TenantRelationshipsMember
93,187us-gaap_FiniteLivedIntangibleAssetsGross
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_TenantRelationshipsMember
 
Finite-lived intangible asset, accumulated (amortization) accretion (66,467)us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_TenantRelationshipsMember
(49,985)us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_TenantRelationshipsMember
 
Total Lease Intangibles [Member]      
Finite-Lived Intangible Assets [Line Items]      
Finite-lived intangible assets, gross 1,728,087us-gaap_FiniteLivedIntangibleAssetsGross
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_TotalLeaseIntangiblesMember
637,473us-gaap_FiniteLivedIntangibleAssetsGross
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_TotalLeaseIntangiblesMember
 
Finite-lived intangible asset, accumulated (amortization) accretion $ (410,512)us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_TotalLeaseIntangiblesMember
$ (326,409)us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= land_TotalLeaseIntangiblesMember