XML 45 R33.htm IDEA: XBRL DOCUMENT
v3.21.2

Leases - Major Tenants - Additional Information (Detail) | 6 Months Ended
--- | ---
Jun. 30, 2021 Property Lease Tenant | Jun. 30, 2020
Leases [Line Items] |  |
Number of significant tenants | Tenant | 2 |
Subsidiaries of Global Partners LP (NYSE GLP) [Member] |  |
Leases [Line Items] |  |
Number of leased properties | Property | 150 |
Number of unitary leases guaranteed by the parent | 3 |
Subsidiaries of Global Partners LP (NYSE GLP) [Member] | Sales Revenue, Net [Member] | Customer Concentration Risk [Member] |  |
Leases [Line Items] |  |
Lease revenue percentage | 15.00% | 16.00%
Subsidiaries of ARKO Corp. (NASDAQ: ARKO) [Member] |  |
Leases [Line Items] |  |
Number of leased properties | Property | 128 |
Number of unitary leases guaranteed by the parent | 4 |
Subsidiaries of ARKO Corp. (NASDAQ: ARKO) [Member] | Sales Revenue, Net [Member] | Customer Concentration Risk [Member] |  |
Leases [Line Items] |  |
Lease revenue percentage | 15.00% | 15.00%
Apro, LLC (d/b/a United Oil) [Member] |  |
Leases [Line Items] |  |
Number of leased properties | Property | 77 |
Number Of Unitary Leases To Tenant | 3 |
Apro, LLC (d/b/a United Oil) [Member] | Sales Revenue, Net [Member] | Customer Concentration Risk [Member] |  |
Leases [Line Items] |  |
Lease revenue percentage | 12.00% | 12.00%
Subsidiaries of Chestnut Petroleum Dist. Inc.[Member] |  |
Leases [Line Items] |  |
Number of leased properties | Property | 74 |
Number of unitary leases | 2 |
Subsidiaries of Chestnut Petroleum Dist. Inc.[Member] | Sales Revenue, Net [Member] | Customer Concentration Risk [Member] |  |
Leases [Line Items] |  |
Lease revenue percentage | 9.00% | 10.00%
Number of leased properties guaranteed | 56 |

X
- Definition Leases. + References No definition available. + Details
Name: | gty_LeasesLineItems
Namespace Prefix: | gty_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The aggregate number of properties currently being leased to subsidiaries of our tenant. + References No definition available. + Details
Name: | gty_NumberOfLeasedProperties
Namespace Prefix: | gty_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition The number of properties in the unitary lease that is guaranteed by the parent company, its principals and affiliates. + References No definition available. + Details
Name: | gty_NumberOfPropertiesInUnitaryLeaseGuaranteed
Namespace Prefix: | gty_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition The number of current tenants that are considered significant. + References No definition available. + Details
Name: | gty_NumberOfSignificantTenants
Namespace Prefix: | gty_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition The number of unitary leases with subsidiaries of the tenant's parent. + References No definition available. + Details
Name: | gty_NumberOfUnitaryLeases
Namespace Prefix: | gty_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition The number of unitary leases that are guaranteed by the parent company. + References No definition available. + Details
Name: | gty_NumberOfUnitaryLeasesGuaranteed
Namespace Prefix: | gty_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition The number of unitary leases leased to tenant. + References No definition available. + Details
Name: | gty_NumberOfUnitaryLeasesToTenant
Namespace Prefix: | gty_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 42 -URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e9054-108599 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 18 -URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6351-108592 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=121572278&loc=d3e13531-108611 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 21 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121572278&loc=d3e13537-108611 Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6404-108592 + Details
Name: | us-gaap_ConcentrationRiskPercentage1
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_LeaseContractualTermAxis=gty_SubsidiariesOfGlobalPartnersLpMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ConcentrationRiskByBenchmarkAxis=us-gaap_SalesRevenueNetMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ConcentrationRiskByTypeAxis=us-gaap_CustomerConcentrationRiskMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LeaseContractualTermAxis=gty_SubsidiariesOfARKOCorpMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LeaseContractualTermAxis=gty_AproLlcMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LeaseContractualTermAxis=gty_SubsidiariesOfChestnutPetroleumDistIncMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |