Name:	gnk_CapacityOfVesselsInDeadweightTonnage
Namespace Prefix:	gnk_
Data Type:	num:massItemType
Balance Type:	na
Period Type:	instant

The capitalized liability related to an existing below-market time charter that is acquired with a vessel purchase which is amortized as an increase in voyage revenue over the remaining term of the existing charter.

No definition available.

Name:	gnk_FairMarketValueOfTimeChartersAcquired
Namespace Prefix:	gnk_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	gnk_FairMarketValueOfTimeChartersAcquiredAmortizationExpenseAbstract
Namespace Prefix:	gnk_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Represents the amount of amortization of the fair market value of time charter expected to be recognized during the next fiscal year following the latest fiscal year.

No definition available.

Name:	gnk_FairMarketValueOfTimeChartersAcquiredAmortizationYearOne
Namespace Prefix:	gnk_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Represents the remaining weighted-average amortization period of fair market value of time charters acquired.

No definition available.

Name:	gnk_FairMarketValueOfTimeChartersAcquiredWeightedAverageAmortizationPeriod
Namespace Prefix:	gnk_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Represents the number of vessels acquired by the entity which had existing below market time charters at the time of the acquisitions.

No definition available.

Name:	gnk_NumberOfVesselsAcquiredHavingBelowMarketTimeCharters
Namespace Prefix:	gnk_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Represents the number of vessels committed to be acquired by the entity under purchase agreement.

No definition available.

Name:	gnk_NumberOfVesselsCommittedToBeAcquiredUnderPurchaseAgreement
Namespace Prefix:	gnk_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Represents the number of vessels purchased under option to be acquired by the entity under purchase agreement.

No definition available.

Name:	gnk_NumberOfVesselsPurchasedUnderOptionToBeAcquiredPerPurchaseAgreement
Namespace Prefix:	gnk_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Represents the number of vessels to be acquired by the entity under purchase agreement.

No definition available.

Name:	gnk_NumberOfVesselsToBeAcquiredUnderPurchaseAgreement
Namespace Prefix:	gnk_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

The value paid for each vessel purchased.

No definition available.

Name:	gnk_PurchasePricePerVessel
Namespace Prefix:	gnk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Represents the value of the below market liability related to time charters which was acquired during the period.

No definition available.

Name:	gnk_SignificantAcquisitionsAndDisposalsLiabilityForTimeChartersAcquired
Namespace Prefix:	gnk_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Amount of interest capitalized during the period.

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Allowance for Funds Used during Construction

-URI http://asc.fasb.org/extlink&oid=6504829

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6450988&loc=d3e26243-108391

Name:	us-gaap_InterestCostsCapitalized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19(b),22(b))

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

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

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

Cash outflow related to other deposits not otherwise defined in the taxonomy.

No definition available.

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

The amount of previously reported deferred or unearned revenue that was recognized as revenue during the period. For cash flows, this element primarily pertains to amortization of deferred credits on long-term arrangements. As a noncash item, it is deducted from net income when calculating cash provided by or used in operations using the indirect method.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 605

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SAB TOPIC 13.A.4(a).Q1)

-URI http://asc.fasb.org/extlink&oid=27012821&loc=d3e214044-122780

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 13

-Section A

-Subsection 1

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

The value of all consideration given or received by the Entity in the significant acquisition or disposal.

No definition available.