Real Estate and Intangible Assets - Summary of Properties Acquired (Detail) (USD $) In Thousands, unless otherwise specified
|
12 Months Ended |
1 Months Ended |
Dec. 31, 2014
sqft
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Dec. 31, 2013
sqft
|
Jul. 31, 2004
|
Oct. 31, 2005
|
Business Acquisition [Line Items] |
|
|
|
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Square Footage (unaudited) |
2,496,634good_AreaOfRealEstateProperties
|
1,085,129good_AreaOfRealEstateProperties
|
|
|
Total Purchase Price |
$ 140,011good_PurchasePrice
|
$ 134,438good_PurchasePrice
|
|
|
Acquisition Expenses |
1,292good_BusinessAcquisitionExpenses
|
761good_BusinessAcquisitionExpenses
|
|
|
Annualized Straight Line Rent |
14,216good_AnnualizedStraightLineRent
|
12,399good_AnnualizedStraightLineRent
|
|
|
Debt Issued |
62,231us-gaap_MortgageLoansOnRealEstateNewMortgageLoans
|
71,795us-gaap_MortgageLoansOnRealEstateNewMortgageLoans
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Canton, North Carolina [Member] |
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Business Acquisition [Line Items] |
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Acquisition Date |
Nov. 01, 2014
|
|
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Square Footage (unaudited) |
365,960good_AreaOfRealEstateProperties / us-gaap_BusinessAcquisitionAxis = good_CantonNorthCarolinaMember
|
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Lease Term |
20 years
|
|
|
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Renewal Options |
2good_NumberOfRenewalOptionUnderLease / us-gaap_BusinessAcquisitionAxis = good_CantonNorthCarolinaMember
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Renewal Options Period |
10 years
|
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Total Purchase Price |
5,550good_PurchasePrice / us-gaap_BusinessAcquisitionAxis = good_CantonNorthCarolinaMember
|
|
5,200good_PurchasePrice / us-gaap_BusinessAcquisitionAxis = good_CantonNorthCarolinaMember
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Annualized Straight Line Rent |
1,343good_AnnualizedStraightLineRent / us-gaap_BusinessAcquisitionAxis = good_CantonNorthCarolinaMember
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Clintonville, WI [Member] |
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|
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Business Acquisition [Line Items] |
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|
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Acquisition Date |
|
Apr. 11, 2013
|
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Square Footage (unaudited) |
|
102,400good_AreaOfRealEstateProperties / us-gaap_BusinessAcquisitionAxis = good_ClintonvilleWiMember
|
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Lease Term |
|
15 years
|
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Total Purchase Price |
|
3,250good_PurchasePrice / us-gaap_BusinessAcquisitionAxis = good_ClintonvilleWiMember
|
|
5,300good_PurchasePrice / us-gaap_BusinessAcquisitionAxis = good_ClintonvilleWiMember
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Annualized Straight Line Rent |
|
961good_AnnualizedStraightLineRent / us-gaap_BusinessAcquisitionAxis = good_ClintonvilleWiMember
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Monroe, MI [Member] |
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Business Acquisition [Line Items] |
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Acquisition Date |
Dec. 23, 2014
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Square Footage (unaudited) |
535,500good_AreaOfRealEstateProperties / us-gaap_BusinessAcquisitionAxis = good_MonroeMember
|
|
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Lease Term |
8 years 6 months
|
|
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Renewal Options |
2good_NumberOfRenewalOptionUnderLease / us-gaap_BusinessAcquisitionAxis = good_MonroeMember
|
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Renewal Options Period |
5 years
|
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Total Purchase Price |
30,750good_PurchasePrice / us-gaap_BusinessAcquisitionAxis = good_MonroeMember
|
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Acquisition Expenses |
68good_BusinessAcquisitionExpenses / us-gaap_BusinessAcquisitionAxis = good_MonroeMember
|
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Annualized Straight Line Rent |
2,523good_AnnualizedStraightLineRent / us-gaap_BusinessAcquisitionAxis = good_MonroeMember
|
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Debt Issued |
18,450us-gaap_MortgageLoansOnRealEstateNewMortgageLoans / us-gaap_BusinessAcquisitionAxis = good_MonroeMember
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Egg Harbor Township, NJ [Member] |
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Business Acquisition [Line Items] |
|
|
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Acquisition Date |
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Mar. 28, 2013
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Square Footage (unaudited) |
|
29,257good_AreaOfRealEstateProperties / us-gaap_BusinessAcquisitionAxis = good_EggHarborTownshipNjMember
|
|
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Lease Term |
|
10 years
|
|
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Renewal Options |
|
1good_NumberOfRenewalOptionUnderLease / us-gaap_BusinessAcquisitionAxis = good_EggHarborTownshipNjMember
|
|
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Renewal Options Period |
|
5 years
|
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Total Purchase Price |
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5,650good_PurchasePrice / us-gaap_BusinessAcquisitionAxis = good_EggHarborTownshipNjMember
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Acquisition Expenses |
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152good_BusinessAcquisitionExpenses / us-gaap_BusinessAcquisitionAxis = good_EggHarborTownshipNjMember
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Annualized Straight Line Rent |
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490good_AnnualizedStraightLineRent / us-gaap_BusinessAcquisitionAxis = good_EggHarborTownshipNjMember
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Debt Issued |
|
3,700us-gaap_MortgageLoansOnRealEstateNewMortgageLoans / us-gaap_BusinessAcquisitionAxis = good_EggHarborTownshipNjMember
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Vance, AL [Member] |
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Business Acquisition [Line Items] |
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Acquisition Date |
|
May 09, 2013
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Square Footage (unaudited) |
|
170,000good_AreaOfRealEstateProperties / us-gaap_BusinessAcquisitionAxis = good_VanceAlMember
|
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Lease Term |
|
10 years
|
|
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Renewal Options |
|
2good_NumberOfRenewalOptionUnderLease / us-gaap_BusinessAcquisitionAxis = good_VanceAlMember
|
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Renewal Options Period |
|
5 years
|
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Total Purchase Price |
|
13,388good_PurchasePrice / us-gaap_BusinessAcquisitionAxis = good_VanceAlMember
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Acquisition Expenses |
|
186good_BusinessAcquisitionExpenses / us-gaap_BusinessAcquisitionAxis = good_VanceAlMember
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Annualized Straight Line Rent |
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1,173good_AnnualizedStraightLineRent / us-gaap_BusinessAcquisitionAxis = good_VanceAlMember
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Blaine, MN [Member] |
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Business Acquisition [Line Items] |
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Acquisition Date |
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May 10, 2013
|
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Square Footage (unaudited) |
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92,275good_AreaOfRealEstateProperties / us-gaap_BusinessAcquisitionAxis = good_BlaineMnMember
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Lease Term |
|
7 years
|
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Renewal Options |
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2good_NumberOfRenewalOptionUnderLease / us-gaap_BusinessAcquisitionAxis = good_BlaineMnMember
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Renewal Options Period |
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5 years
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Total Purchase Price |
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14,450good_PurchasePrice / us-gaap_BusinessAcquisitionAxis = good_BlaineMnMember
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Acquisition Expenses |
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79good_BusinessAcquisitionExpenses / us-gaap_BusinessAcquisitionAxis = good_BlaineMnMember
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Annualized Straight Line Rent |
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1,475good_AnnualizedStraightLineRent / us-gaap_BusinessAcquisitionAxis = good_BlaineMnMember
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Debt Issued |
|
8,200us-gaap_MortgageLoansOnRealEstateNewMortgageLoans / us-gaap_BusinessAcquisitionAxis = good_BlaineMnMember
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Austin, Texas [Member] |
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Business Acquisition [Line Items] |
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Acquisition Date |
|
Jul. 09, 2013
|
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Square Footage (unaudited) |
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320,000good_AreaOfRealEstateProperties / us-gaap_BusinessAcquisitionAxis = good_AustinTxMember
|
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Lease Term |
|
7 years
|
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Renewal Options |
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3good_NumberOfRenewalOptionUnderLease / us-gaap_BusinessAcquisitionAxis = good_AustinTxMember
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Renewal Options Period |
|
3 years
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Total Purchase Price |
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57,000good_PurchasePrice / us-gaap_BusinessAcquisitionAxis = good_AustinTxMember
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Acquisition Expenses |
|
155good_BusinessAcquisitionExpenses / us-gaap_BusinessAcquisitionAxis = good_AustinTxMember
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Annualized Straight Line Rent |
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4,641good_AnnualizedStraightLineRent / us-gaap_BusinessAcquisitionAxis = good_AustinTxMember
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Debt Issued |
|
35,300us-gaap_MortgageLoansOnRealEstateNewMortgageLoans / us-gaap_BusinessAcquisitionAxis = good_AustinTxMember
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Allen, TX [Member] |
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Business Acquisition [Line Items] |
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Acquisition Date |
Mar. 27, 2014
|
Jul. 10, 2013
|
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Square Footage (unaudited) |
21,154good_AreaOfRealEstateProperties / us-gaap_BusinessAcquisitionAxis = good_AllenTxMember
|
115,200good_AreaOfRealEstateProperties / us-gaap_BusinessAcquisitionAxis = good_AllenTxMember
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Lease Term |
12 years
|
9 years
|
|
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Renewal Options |
4good_NumberOfRenewalOptionUnderLease / us-gaap_BusinessAcquisitionAxis = good_AllenTxMember
|
2good_NumberOfRenewalOptionUnderLease / us-gaap_BusinessAcquisitionAxis = good_AllenTxMember
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Renewal Options Period |
5 years
|
5 years
|
|
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Total Purchase Price |
5,525good_PurchasePrice / us-gaap_BusinessAcquisitionAxis = good_AllenTxMember
|
15,150good_PurchasePrice / us-gaap_BusinessAcquisitionAxis = good_AllenTxMember
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Acquisition Expenses |
33good_BusinessAcquisitionExpenses / us-gaap_BusinessAcquisitionAxis = good_AllenTxMember
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81good_BusinessAcquisitionExpenses / us-gaap_BusinessAcquisitionAxis = good_AllenTxMember
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Annualized Straight Line Rent |
570good_AnnualizedStraightLineRent / us-gaap_BusinessAcquisitionAxis = good_AllenTxMember
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1,478good_AnnualizedStraightLineRent / us-gaap_BusinessAcquisitionAxis = good_AllenTxMember
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Debt Issued |
3,481us-gaap_MortgageLoansOnRealEstateNewMortgageLoans / us-gaap_BusinessAcquisitionAxis = good_AllenTxMember
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8,900us-gaap_MortgageLoansOnRealEstateNewMortgageLoans / us-gaap_BusinessAcquisitionAxis = good_AllenTxMember
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Englewood, CO [Member] |
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Business Acquisition [Line Items] |
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Acquisition Date |
|
Dec. 11, 2013
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Square Footage (unaudited) |
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99,797good_AreaOfRealEstateProperties / us-gaap_BusinessAcquisitionAxis = good_EnglewoodCoMember
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Lease Term |
|
8 years
|
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Renewal Options |
|
2good_NumberOfRenewalOptionUnderLease / us-gaap_BusinessAcquisitionAxis = good_EnglewoodCoMember
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Renewal Options Period |
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5 years
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Total Purchase Price |
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18,250good_PurchasePrice / us-gaap_BusinessAcquisitionAxis = good_EnglewoodCoMember
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Acquisition Expenses |
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66good_BusinessAcquisitionExpenses / us-gaap_BusinessAcquisitionAxis = good_EnglewoodCoMember
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Annualized Straight Line Rent |
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1,497good_AnnualizedStraightLineRent / us-gaap_BusinessAcquisitionAxis = good_EnglewoodCoMember
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Debt Issued |
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11,315us-gaap_MortgageLoansOnRealEstateNewMortgageLoans / us-gaap_BusinessAcquisitionAxis = good_EnglewoodCoMember
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Novi, MI [Member] |
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Business Acquisition [Line Items] |
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Acquisition Date |
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Dec. 27, 2013
|
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Square Footage (unaudited) |
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156,200good_AreaOfRealEstateProperties / us-gaap_BusinessAcquisitionAxis = good_NoviMiMember
|
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Lease Term |
|
10 years
|
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Renewal Options |
|
1good_NumberOfRenewalOptionUnderLease / us-gaap_BusinessAcquisitionAxis = good_NoviMiMember
|
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|
Renewal Options Period |
|
5 years
|
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Total Purchase Price |
|
7,300good_PurchasePrice / us-gaap_BusinessAcquisitionAxis = good_NoviMiMember
|
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Acquisition Expenses |
|
42good_BusinessAcquisitionExpenses / us-gaap_BusinessAcquisitionAxis = good_NoviMiMember
|
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Annualized Straight Line Rent |
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684good_AnnualizedStraightLineRent / us-gaap_BusinessAcquisitionAxis = good_NoviMiMember
|
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Debt Issued |
|
4,380us-gaap_MortgageLoansOnRealEstateNewMortgageLoans / us-gaap_BusinessAcquisitionAxis = good_NoviMiMember
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Colleyville, TX [Member] |
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Business Acquisition [Line Items] |
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Acquisition Date |
Mar. 27, 2014
|
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Square Footage (unaudited) |
20,355good_AreaOfRealEstateProperties / us-gaap_BusinessAcquisitionAxis = good_ColleyvilletxMember
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Lease Term |
12 years
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Renewal Options |
4good_NumberOfRenewalOptionUnderLease / us-gaap_BusinessAcquisitionAxis = good_ColleyvilletxMember
|
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Renewal Options Period |
5 years
|
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Total Purchase Price |
4,523good_PurchasePrice / us-gaap_BusinessAcquisitionAxis = good_ColleyvilletxMember
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Acquisition Expenses |
33good_BusinessAcquisitionExpenses / us-gaap_BusinessAcquisitionAxis = good_ColleyvilletxMember
|
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|
Annualized Straight Line Rent |
467good_AnnualizedStraightLineRent / us-gaap_BusinessAcquisitionAxis = good_ColleyvilletxMember
|
|
|
|
Debt Issued |
2,849us-gaap_MortgageLoansOnRealEstateNewMortgageLoans / us-gaap_BusinessAcquisitionAxis = good_ColleyvilletxMember
|
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Rancho Cordova, CA [Member] |
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Business Acquisition [Line Items] |
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Acquisition Date |
Apr. 22, 2014
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Square Footage (unaudited) |
61,358good_AreaOfRealEstateProperties / us-gaap_BusinessAcquisitionAxis = good_RanchoCordovaCaliforniaMember
|
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Lease Term |
10 years
|
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Renewal Options |
1good_NumberOfRenewalOptionUnderLease / us-gaap_BusinessAcquisitionAxis = good_RanchoCordovaCaliforniaMember
|
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Renewal Options Period |
5 years
|
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Total Purchase Price |
8,225good_PurchasePrice / us-gaap_BusinessAcquisitionAxis = good_RanchoCordovaCaliforniaMember
|
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Acquisition Expenses |
73good_BusinessAcquisitionExpenses / us-gaap_BusinessAcquisitionAxis = good_RanchoCordovaCaliforniaMember
|
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Annualized Straight Line Rent |
902good_AnnualizedStraightLineRent / us-gaap_BusinessAcquisitionAxis = good_RanchoCordovaCaliforniaMember
|
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|
Debt Issued |
4,935us-gaap_MortgageLoansOnRealEstateNewMortgageLoans / us-gaap_BusinessAcquisitionAxis = good_RanchoCordovaCaliforniaMember
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Coppell, TX [Member] |
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Business Acquisition [Line Items] |
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Acquisition Date |
May 08, 2014
|
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Square Footage (unaudited) |
21,171good_AreaOfRealEstateProperties / us-gaap_BusinessAcquisitionAxis = good_CoppelltxMember
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Lease Term |
12 years
|
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Renewal Options |
4good_NumberOfRenewalOptionUnderLease / us-gaap_BusinessAcquisitionAxis = good_CoppelltxMember
|
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Renewal Options Period |
5 years
|
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Total Purchase Price |
5,838good_PurchasePrice / us-gaap_BusinessAcquisitionAxis = good_CoppelltxMember
|
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Acquisition Expenses |
26good_BusinessAcquisitionExpenses / us-gaap_BusinessAcquisitionAxis = good_CoppelltxMember
|
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Annualized Straight Line Rent |
601good_AnnualizedStraightLineRent / us-gaap_BusinessAcquisitionAxis = good_CoppelltxMember
|
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Debt Issued |
3,816us-gaap_MortgageLoansOnRealEstateNewMortgageLoans / us-gaap_BusinessAcquisitionAxis = good_CoppelltxMember
|
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Columbus, OH [Member] |
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Business Acquisition [Line Items] |
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Acquisition Date |
May 13, 2014
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Square Footage (unaudited) |
114,786good_AreaOfRealEstateProperties / us-gaap_BusinessAcquisitionAxis = good_ColumbusOHMember
|
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Lease Term |
9 years 6 months
|
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Total Purchase Price |
11,800good_PurchasePrice / us-gaap_BusinessAcquisitionAxis = good_ColumbusOHMember
|
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Acquisition Expenses |
70good_BusinessAcquisitionExpenses / us-gaap_BusinessAcquisitionAxis = good_ColumbusOHMember
|
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Annualized Straight Line Rent |
1,278good_AnnualizedStraightLineRent / us-gaap_BusinessAcquisitionAxis = good_ColumbusOHMember
|
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Taylor, PA [Member] |
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Business Acquisition [Line Items] |
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|
Acquisition Date |
Jun. 09, 2014
|
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|
Square Footage (unaudited) |
955,935good_AreaOfRealEstateProperties / us-gaap_BusinessAcquisitionAxis = good_TaylorpaMember
|
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|
|
Lease Term |
10 years
|
|
|
|
Renewal Options |
4good_NumberOfRenewalOptionUnderLease / us-gaap_BusinessAcquisitionAxis = good_TaylorpaMember
|
|
|
|
Renewal Options Period |
5 years
|
|
|
|
Total Purchase Price |
39,000good_PurchasePrice / us-gaap_BusinessAcquisitionAxis = good_TaylorpaMember
|
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|
Acquisition Expenses |
730good_BusinessAcquisitionExpenses / us-gaap_BusinessAcquisitionAxis = good_TaylorpaMember
|
|
|
|
Annualized Straight Line Rent |
3,400good_AnnualizedStraightLineRent / us-gaap_BusinessAcquisitionAxis = good_TaylorpaMember
|
|
|
|
Debt Issued |
22,600us-gaap_MortgageLoansOnRealEstateNewMortgageLoans / us-gaap_BusinessAcquisitionAxis = good_TaylorpaMember
|
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|
Aurora, CO [Member] |
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Business Acquisition [Line Items] |
|
|
|
|
Acquisition Date |
Jul. 01, 2014
|
|
|
|
Square Footage (unaudited) |
124,800good_AreaOfRealEstateProperties / us-gaap_BusinessAcquisitionAxis = good_AuroraMember
|
|
|
|
Lease Term |
15 years
|
|
|
|
Renewal Options |
2good_NumberOfRenewalOptionUnderLease / us-gaap_BusinessAcquisitionAxis = good_AuroraMember
|
|
|
|
Renewal Options Period |
5 years
|
|
|
|
Total Purchase Price |
8,300good_PurchasePrice / us-gaap_BusinessAcquisitionAxis = good_AuroraMember
|
|
|
|
Acquisition Expenses |
93good_BusinessAcquisitionExpenses / us-gaap_BusinessAcquisitionAxis = good_AuroraMember
|
|
|
|
Annualized Straight Line Rent |
768good_AnnualizedStraightLineRent / us-gaap_BusinessAcquisitionAxis = good_AuroraMember
|
|
|
|
Indianapolis, IN [Member] |
|
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|
Business Acquisition [Line Items] |
|
|
|
|
Acquisition Date |
Sep. 03, 2014
|
|
|
|
Square Footage (unaudited) |
86,495good_AreaOfRealEstateProperties / us-gaap_BusinessAcquisitionAxis = good_IndianapolisMember
|
|
|
|
Lease Term |
11 years 6 months
|
|
|
|
Renewal Options |
2good_NumberOfRenewalOptionUnderLease / us-gaap_BusinessAcquisitionAxis = good_IndianapolisMember
|
|
|
|
Renewal Options Period |
5 years
|
|
|
|
Total Purchase Price |
10,500good_PurchasePrice / us-gaap_BusinessAcquisitionAxis = good_IndianapolisMember
|
|
|
|
Acquisition Expenses |
63good_BusinessAcquisitionExpenses / us-gaap_BusinessAcquisitionAxis = good_IndianapolisMember
|
|
|
|
Annualized Straight Line Rent |
1,504good_AnnualizedStraightLineRent / us-gaap_BusinessAcquisitionAxis = good_IndianapolisMember
|
|
|
|
Debt Issued |
6,100us-gaap_MortgageLoansOnRealEstateNewMortgageLoans / us-gaap_BusinessAcquisitionAxis = good_IndianapolisMember
|
|
|
|
Denver, CO [Member] |
|
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|
Business Acquisition [Line Items] |
|
|
|
|
Acquisition Date |
Oct. 31, 2014
|
|
|
|
Square Footage (unaudited) |
189,120good_AreaOfRealEstateProperties / us-gaap_BusinessAcquisitionAxis = good_DenverCoMember
|
|
|
|
Lease Term |
10 years
|
|
|
|
Renewal Options |
2good_NumberOfRenewalOptionUnderLease / us-gaap_BusinessAcquisitionAxis = good_DenverCoMember
|
|
|
|
Renewal Options Period |
10 years
|
|
|
|
Total Purchase Price |
10,000good_PurchasePrice / us-gaap_BusinessAcquisitionAxis = good_DenverCoMember
|
|
|
|
Acquisition Expenses |
103good_BusinessAcquisitionExpenses / us-gaap_BusinessAcquisitionAxis = good_DenverCoMember
|
|
|
|
Annualized Straight Line Rent |
$ 860good_AnnualizedStraightLineRent / us-gaap_BusinessAcquisitionAxis = good_DenverCoMember
|
|
|
|