Name:	gnk_DebtCovenantCollateralVesselsReplacementPeriod
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Data Type:	xbrli:durationItemType
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Debt covenant unrestricted cash and cash equivalents minimum per vessel.

No definition available.

Name:	gnk_DebtCovenantUnrestrictedCashMinimumPerVessel
Namespace Prefix:	gnk_
Data Type:	xbrli:monetaryItemType
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Period Type:	instant

Debt covenant pertaining to unrestricted cash and cash equivalents to total indebtedness.

No definition available.

Name:	gnk_DebtCovenantUnrestrictedCashPercentOfIndebtedness
Namespace Prefix:	gnk_
Data Type:	dtr-types:percentItemType
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Represents the age of collateral vessels for increase of borrowings.

No definition available.

Name:	gnk_DebtInstrumentAgeOfCollateralVesselsForIncreaseOfBorrowings
Namespace Prefix:	gnk_
Data Type:	xbrli:durationItemType
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Represents increase or decrease in the applicable margin based on the entity's performance regarding emissions targets.

No definition available.

Name:	gnk_DebtInstrumentMarginIncreaseDecreaseBasedOnPerformanceEmissionsTargets
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Data Type:	dtr-types:percentItemType
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Additional borrowing capacity under the credit facility.

No definition available.

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

The amount of consecutive quarterly commitment reduction at the end of the reporting period.

No definition available.

Name:	gnk_LineOfCreditFacilityConsecutiveQuarterlyCommitmentReductions
Namespace Prefix:	gnk_
Data Type:	xbrli:monetaryItemType
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Period Type:	instant

Represents the aggregate fair value of the mortgaged vessels to be maintained as a percentage of aggregate outstanding principal amount as per the terms of the credit facilities' covenants.

No definition available.

Name:	gnk_LineOfCreditFacilityCovenantFairMarketValueOfMortgagedVesselsAsPercentageOfAggregateOutstandingPrincipalAmount
Namespace Prefix:	gnk_
Data Type:	dtr-types:percentItemType
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Ratio of the principal amount of debt outstanding to the collateral.

No definition available.

Name:	gnk_LoanToValueRatio
Namespace Prefix:	gnk_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Represents the maximum ratio of total debt outstanding to total capitalization.

No definition available.

Name:	gnk_MaximumTotalDebtToTotalCapitalizationRatio
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Data Type:	xbrli:pureItemType
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Number of unencumbered vessels delivered during the period.

No definition available.

Name:	gnk_NumberOfUnencumberedVesselsDelivered
Namespace Prefix:	gnk_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

Represents the number of vessels to serve as collateral under debt agreement.

No definition available.

Name:	gnk_NumberOfVesselsToServeAsCollateralUnderDebtAgreement
Namespace Prefix:	gnk_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

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

No definition available.

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

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.

No definition available.

Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
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Period Type:	duration

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

No definition available.

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

Period remaining on line of credit facility before it terminates, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

Name:	us-gaap_LineOfCreditFacilityExpirationPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

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

The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

No definition available.

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

The cash inflow from amounts received from issuance of long-term debt that is wholly or partially secured by collateral. Excludes proceeds from tax exempt secured debt.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3255-108585

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

The cash outflow to repay long-term debt that is wholly or partially secured by collateral. Excludes repayments of tax exempt secured debt.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3291-108585

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

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

Name:	us-gaap_DebtInstrumentAxis=gnk_TermLoanFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	srt_StatementScenarioAxis=gnk_CollateralVesselsLessThanFiveYearsOldMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	srt_StatementScenarioAxis=gnk_CollateralVesselsAtLeastFiveYearsOldButNotOlderThanSevenYearsMember
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Name:	us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
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Name:	srt_RangeAxis=srt_MinimumMember
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