The number of leased items affected by the termination of the lease.

No definition available.

Name:	glp_EarlyTerminationOfLeaseNumberOfItemsReleased
Namespace Prefix:	glp_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of the liability to provide fleet management services at the balance sheet date, resulting from receipt of incremental costs from counterparty.

+ References

No definition available.

+ Details

Name:	glp_FleetManagementAgreementLiabilityForIncrementalCosts
Namespace Prefix:	glp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The number of leasing agreements.

+ References

No definition available.

+ Details

Name:	glp_NumberOfLeaseAgreements
Namespace Prefix:	glp_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the number of gasoline stations and/or convenience stores disposed of by sale or other means.

+ References

No definition available.

+ Details

Name:	glp_NumberOfLocationsDisposed
Namespace Prefix:	glp_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of sale leaseback transactions.

+ References

No definition available.

+ Details

Name:	glp_NumberOfSaleLeasebackTransactions
Namespace Prefix:	glp_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Gain (loss) related to the termination of a contract between the parties. The termination may be due to many causes including early termination of a lease by a lessee, a breach of contract by one party, or a failure to perform.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869

+ Details

Name:	us-gaap_GainLossOnContractTermination
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of gain (loss) on termination of lease before expiration of lease term.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 40
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=77888415&loc=SL77918607-209975

+ Details

Name:	us-gaap_GainLossOnTerminationOfLease
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Indicates (true false) whether practical expedients are elected for not reassessing whether any expired or existing contract is or contains lease, lease classification for expired or existing lease, and initial direct cost for any existing lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 10
-Section 65
-Paragraph 1
-Subparagraph (j)
-URI http://asc.fasb.org/extlink&oid=119364159&loc=SL77916155-209984

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 10
-Section 65
-Paragraph 1
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=119364159&loc=SL77916155-209984

+ Details

Name:	us-gaap_LeasePracticalExpedientsPackage
Namespace Prefix:	us-gaap_
Data Type:	xbrli:booleanItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_LesseeDisclosureAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Term of lessee's operating lease renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918673-209980

+ Details

Name:	us-gaap_LesseeOperatingLeaseRenewalTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

- Definition

Term of lessee's operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

+ Details

Name:	us-gaap_LesseeOperatingLeaseTermOfContract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=glp_GasolineStationsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=glp_UnrelatedOilTerminalsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=glp_DedicatedStorageFacilitiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=glp_BargesAndRailcarsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=glp_OfficeSpaceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_ComputerEquipmentMember
Namespace Prefix:
Data Type:	na
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Period Type:

Summary of Significant Accounting Policies - Leases (Details) $ in Thousands	1 Months Ended		3 Months Ended	12 Months Ended
	Jun. 30, 2016 item	Jun. 30, 2015 item	Sep. 30, 2018 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 item
Leases
Number of master unitary leasing agreements		3
Number of sale-leaseback transactions		2
Number of locations divested	30
Lease, Practical Expedients, Package [true false]				true
Number of railcars released							1,610
Lease exit and termination gain, ASC842 \| $			$ 3,500	$ 493		$ (16,194)
Lease exit gain (loss) \| $					$ 3,506
Remaining accrued incremental costs \| $				$ 1,300
Maximum
Leases
Renewal term				30 years
Gasoline station buildings, improvements and storage tanks \| Minimum
Leases
Lease term				1 year
Gasoline station buildings, improvements and storage tanks \| Maximum
Leases
Lease term				20 years
Terminal and Throughput Leases \| Minimum
Leases
Lease term				1 year
Terminal and Throughput Leases \| Maximum
Leases
Lease term				5 years
Dedicated Storage Facilities [Member] \| Minimum
Leases
Lease term				1 year
Dedicated Storage Facilities [Member] \| Maximum
Leases
Lease term				5 years
Barges And Railcars [Member] \| Minimum
Leases
Lease term				1 year
Barges And Railcars [Member] \| Maximum
Leases
Lease term				10 years
Office Space [Member] \| Minimum
Leases
Lease term				1 year
Office Space [Member] \| Maximum
Leases
Lease term				12 years
Computer Equipment [Member] \| Minimum
Leases
Lease term				1 year
Computer Equipment [Member] \| Maximum
Leases
Lease term				5 years