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Represents the monthly payments that the lessee is obligated to make or can be required to make in connection with a property under the terms of an agreement classified as an operating lease.

No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Represents the period of lease agreements entered into by the entity.

No definition available.

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Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Represents the obligation of sublessor towards the cost of alterations to the assets under the lease agreement.

No definition available.

Name:	gnk_OperatingLeasesObligationOfSublessorTowardsCostOfAlterationsOfAssetUnderLease
Namespace Prefix:	gnk_
Data Type:	xbrli:monetaryItemType
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For a classified balance sheet, the cumulative difference between the rental income or payments required by a lease agreement and the rental income or expense recognized on a straight-line basis, or other systematic and rational basis more representative of the time pattern in which use or benefit is granted or derived from the leased property, expected to be recognized in income or expense, by the lessor or lessee, respectively, more than one year after the balance sheet date.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 20

-Section 25

-Paragraph 2

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=7501430&loc=d3e39927-112707

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.26(c))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Period Type:	instant

Amount of rent expense incurred for leased assets, including but not limited to, furniture and equipment, that is not directly or indirectly associated with the manufacture, sale or creation of a product or product line.

No definition available.

Name:	us-gaap_LeaseAndRentalExpense
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Name:	us-gaap_OperatingLeasedAssetsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 20

-Section 50

-Paragraph 2

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6453985&loc=d3e41502-112717

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 10

-Section 55

-Paragraph 40

-Subparagraph (Note 3)

-URI http://asc.fasb.org/extlink&oid=6584154&loc=d3e38371-112697

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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

Name:	us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears
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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

Name:	us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
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Period Type:	instant

Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
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Period Type:	instant

Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the remainder of the fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

No definition available.

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

Name:	gnk_LeaseAgreementsTypeAxis=gnk_LeaseAgreementForOfficeSpaceEnteredApril2011Member
Namespace Prefix:
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Name:	gnk_OperatingLeaseRentExpensePeriodAxis=gnk_OperatingLeaseRentExpensePeriodAfter31May2015UntilEndOfLeaseTermMember
Namespace Prefix:
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Name:	gnk_OperatingLeaseRentExpensePeriodAxis=gnk_OperatingLeaseRentExpensePeriodFrom1May2023To30September2025Member
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Name:	gnk_OperatingLeaseRentExpensePeriodAxis=gnk_OperatingLeaseRentExpensePeriodFrom1October2018To30April2023Member
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