The number of periodic payment installments in which the debt is to be repaid.

No definition available.

Name:	gsl_DebtInstrumentNumberOfPaymentInstallments
Namespace Prefix:	gsl_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The carrying amount (book value) of the lease liability recognized on the balance sheet after a sale and leaseback transaction.

+ References

No definition available.

+ Details

Name:	gsl_FinancialLiabilityCarryingAmount
Namespace Prefix:	gsl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Face amount of financial liability at time of sale and leaseback agreement.

+ References

No definition available.

+ Details

Name:	gsl_FinancialLiabilityFaceAmount
Namespace Prefix:	gsl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The number of sale and leaseback agreements.

+ References

No definition available.

+ Details

Name:	gsl_NumberOfSaleAndLeasebackAgreements
Namespace Prefix:	gsl_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of vessels financed.

+ References

No definition available.

+ Details

Name:	gsl_NumberOfVesselsFinanced
Namespace Prefix:	gsl_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Description of the frequency of periodic payments (monthly, quarterly, annual).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22)(a)(1))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S50
-Paragraph 9
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480657/210-10-S50-9

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477734/942-470-50-3

+ Details

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

- Definition

Date when the debt instrument is scheduled to be fully repaid, in YYYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477657/942-210-S45-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478478/942-210-S50-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S50
-Paragraph 9
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480657/210-10-S50-9

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22)(a)(2))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)(i)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

Reference 7: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

Reference 8: http://www.xbrl.org/2003/role/exampleRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B

+ Details

Name:	us-gaap_DebtInstrumentMaturityDate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of the required periodic payments including both interest and principal payments.

+ References

+ Details

Name:	us-gaap_DebtInstrumentPeriodicPayment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of payment greater than the preceding installment payments to be paid at final maturity date of debt.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentPeriodicPaymentTermsBalloonPaymentToBePaid
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Indicates type of variable interest rate on debt instrument.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 470
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477734/942-470-50-3

+ Details

Name:	us-gaap_DebtInstrumentVariableInterestRateTypeExtensibleEnumeration
Namespace Prefix:	us-gaap_
Data Type:	enum2:enumerationSetItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477657/942-210-S45-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478478/942-210-S50-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(13)(3)(a))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S50
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480657/210-10-S50-8

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(19)(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480738/235-10-S50-1

Reference 7: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(f))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480678/235-10-S99-1

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481544/470-10-50-6

Reference 9: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481544/470-10-50-6

+ Details

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

- Details

Name:	us-gaap_DebtInstrumentAxis=gsl_SaleAndLeasebackAgreementsCMBFLFourVesselsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SaleLeasebackTransactionDescriptionAxis=gsl_SaleAndLeasebackAgreementsFirstMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SaleLeasebackTransactionDescriptionAxis=gsl_SaleAndLeasebackAgreementsSecondMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SaleLeasebackTransactionDescriptionAxis=gsl_SaleAndLeasebackAgreementThirdMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SaleLeasebackTransactionDescriptionAxis=gsl_SaleAndLeasebackAgreementFirstSecondAndThirdMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SaleLeasebackTransactionDescriptionAxis=gsl_SaleAndLeasebackAgreementFourMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SaleLeasebackTransactionDescriptionAxis=gsl_SaleAndLeasebackAgreementSupplementalAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentRedemptionPeriodAxis=us-gaap_DebtInstrumentRedemptionPeriodOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentRedemptionPeriodAxis=us-gaap_DebtInstrumentRedemptionPeriodTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Long-Term Debt - $120,000 Sale and Leaseback Agreements - CMBFL Four Vessels (Details) - CMBFL Four Vessels [Member]		6 Months Ended
	Aug. 26, 2021 USD ($) Vessel Agreement	Jun. 30, 2026 USD ($) Installment	Oct. 13, 2021 USD ($)	Sep. 30, 2021 USD ($)
Long-Term Debt [Abstract]
Face amount	$ 120,000,000
Number of sale and leaseback agreements \| Agreement	4
Number of vessels financed (in Vessel) \| Vessel	4
Outstanding balance		$ 34,912,000
Balloon payment		$ 7,000,000
Debt Instrument, Variable Interest Rate, Type [Extensible Enumeration]		SOFR [Member]
Margin on variable rate		3.25%
Sale and Leasback Agreement - One [member]
Long-Term Debt [Abstract]
Face amount	$ 30,000,000
Sale and Leaseback Agreement - Two [Member]
Long-Term Debt [Abstract]
Face amount	30,000,000
Sale and Leaseback Agreement - Three [Member]
Long-Term Debt [Abstract]
Face amount	$ 30,000,000
Sale and Leaseback Agreement - First, Second and Third [Member]
Long-Term Debt [Abstract]
Outstanding balance				$ 90,000,000
Maturity date		Sep. 30, 2027
Sale and Leaseback Agreement - Four [Member]
Long-Term Debt [Abstract]
Outstanding balance			$ 30,000,000
Maturity date		Oct. 31, 2027
Supplemental Agreement [Member]
Long-Term Debt [Abstract]
Debt Instrument, Variable Interest Rate, Type [Extensible Enumeration]		SOFR [Member]
Margin on variable rate		2.75%
Debt Redemption Period, One [Member]
Long-Term Debt [Abstract]
Number of payment installments (in Installment) \| Installment		12
Periodic installment payment		$ 1,587,500
Frequency of periodic payment		quarterly
Debt Redemption Period, Two [Member]
Long-Term Debt [Abstract]
Number of payment installments (in Installment) \| Installment		12
Periodic installment payment		$ 329,200
Frequency of periodic payment		quarterly