Quarterly report pursuant to Section 13 or 15(d)

Subsequent Events - Additional Information (Detail)

v2.4.1.9
Subsequent Events - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified
0 Months Ended 3 Months Ended 0 Months Ended
Feb. 27, 2015
Mar. 31, 2015
Apr. 28, 2015
Jul. 25, 2014
Apr. 14, 2015
Subsequent Event [Line Items]          
Estimated percentage of rate of Interest       22.00%good_EffectOfMortgageLoanRateOfReturnEstimate  
Loan maturity description   This loan matures upon the earlier of April 2016 or the sale of the transitional care facility, which is anticipated to occur in November 2015.      
Early termination penalty $ 1.0good_LeaseTerminationFees        
Effective termination date   Dec. 31, 2017      
Lease termination description   Termination option, which allows the tenant to terminate their lease effective December 31, 2017, upon paying a termination penalty of approximately $1.0 million on or before March 31, 2017. All other terms and conditions of the lease remain in full force and effect.      
Austin Texas [Member]          
Subsequent Event [Line Items]          
Effective termination date   Dec. 31, 2017      
Lease termination description   Termination option, which allows the tenant to terminate its lease effective December 31, 2017, upon paying a termination penalty of approximately $1.4 million on or before March 31, 2017. This modification forfeits the tenant's right to $0.6 million in tenant improvement allowance, provided in an earlier amendment. All other terms and conditions of the lease remain in full force and effect.      
Subsequent Event [Member]          
Subsequent Event [Line Items]          
Interim financing loan         0.3good_InterimFinancingLoanForAcquisition
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember
Estimated percentage of rate of Interest         22.00%good_EffectOfMortgageLoanRateOfReturnEstimate
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember
Subsequent Event [Member] | Austin Texas [Member]          
Subsequent Event [Line Items]          
Early termination penalty     1.1good_LeaseTerminationFees
/ invest_InvestmentGeographicRegionAxis
= good_AustinTexasMember
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember
   
Forfeiture of tenant improvement allowance     $ 0.6good_ForfeitureOfTenantImprovementAllowance
/ invest_InvestmentGeographicRegionAxis
= good_AustinTexasMember
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember