Quarterly report pursuant to Section 13 or 15(d)

Stockholders' Equity - Monthly Distributions Declared and Paid by Company's Board of Directors (Detail)

v2.4.1.9
Stockholders' Equity - Monthly Distributions Declared and Paid by Company's Board of Directors (Detail) (USD $)
3 Months Ended 0 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Feb. 03, 2015
Jan. 31, 2014
Feb. 27, 2015
Feb. 28, 2014
Mar. 31, 2015
Mar. 31, 2014
Class of Stock [Line Items]                
Distributions per Common Share $ 0.105us-gaap_CommonStockDividendsPerShareCashPaid $ 0.090us-gaap_CommonStockDividendsPerShareCashPaid            
Monthly Distribution One [Member]                
Class of Stock [Line Items]                
Dividend Declaration Date Jan. 13, 2015 Jan. 07, 2014            
Record Date Jan. 23, 2015 Jan. 22, 2014            
Dividend Payment Date Feb. 03, 2015 Jan. 31, 2014            
Distributions per Common Share     $ 0.035us-gaap_CommonStockDividendsPerShareCashPaid
/ us-gaap_DividendsAxis
= land_MonthlyDistributionOneMember
$ 0.030us-gaap_CommonStockDividendsPerShareCashPaid
/ us-gaap_DividendsAxis
= land_MonthlyDistributionOneMember
       
Monthly Distribution Two [Member]                
Class of Stock [Line Items]                
Dividend Declaration Date Jan. 13, 2015 Jan. 07, 2014            
Record Date Feb. 18, 2015 Feb. 19, 2014            
Dividend Payment Date Feb. 27, 2015 Feb. 28, 2014            
Distributions per Common Share         $ 0.035us-gaap_CommonStockDividendsPerShareCashPaid
/ us-gaap_DividendsAxis
= land_MonthlyDistributionTwoMember
$ 0.030us-gaap_CommonStockDividendsPerShareCashPaid
/ us-gaap_DividendsAxis
= land_MonthlyDistributionTwoMember
   
Monthly Distribution Three [Member]                
Class of Stock [Line Items]                
Dividend Declaration Date Jan. 13, 2015 Jan. 07, 2014            
Record Date Mar. 20, 2015 Mar. 17, 2014            
Dividend Payment Date Mar. 31, 2015 Mar. 31, 2014            
Distributions per Common Share             $ 0.035us-gaap_CommonStockDividendsPerShareCashPaid
/ us-gaap_DividendsAxis
= land_MonthlyDistributionThreeMember
$ 0.030us-gaap_CommonStockDividendsPerShareCashPaid
/ us-gaap_DividendsAxis
= land_MonthlyDistributionThreeMember