Name:	gnk_DebtInstrumentCovenantTotalCashAndCashEquivalents
Namespace Prefix:	gnk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Debt covenant pertaining to the percentage of total cash and cash equivalents to total indebtedness, in which the entity may pay dividends or repurchase of stock.

No definition available.

Name:	gnk_DebtInstrumentCovenantTotalCashAndCashEquivalentsToTotalIndebtednessPercentage
Namespace Prefix:	gnk_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

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:	num:percentItemType
Balance Type:	na
Period Type:	instant

Number of credit facilities amended during the period.

No definition available.

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

The percentage limit of consolidated net income for dividends to be paid if collateral maintenance test is met.

No definition available.

Name:	gnk_PercentageLimitOfConsolidatedNetIncomeForPaymentOfDistributions
Namespace Prefix:	gnk_
Data Type:	num: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_LineOfCreditFacilityLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
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=6877327&loc=d3e13212-122682

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

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

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

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