Represents brokerage commission payable in percentage to the third party.

No definition available.

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

- Definition

Represents the capacity of vessels expressed in deadweight tonnage (dwt), a measure of weight a ship is carrying or can safely carry.

+ References

No definition available.

+ Details

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

- Definition

The debt covenant period for replacement of new vessel having an equal or greater appraised value if in compliance with collateral maintenance test.

+ References

No definition available.

+ Details

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

- Definition

Amount of vessel sale proceeds utilized as a loan repayment due to replacement vessel was not added as collateral with period stipulated under credit facility.

+ References

No definition available.

+ Details

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

- Definition

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

+ References

No definition available.

+ Details

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

- Definition

Represents the period for which the net sale proceeds from sale of vessels will remain classified as restricted cash following the sale date if or until a replacement vessel or vessels meeting certain requirements are added as collateral under the facility.

+ References

No definition available.

+ Details

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

- Definition

The value paid for each vessel purchased.

+ References

No definition available.

+ Details

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

- Definition

Aggregate dividends declared during the period for each share of common stock outstanding.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770

+ Details

Name:	us-gaap_CommonStockDividendsPerShareDeclared
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Carrying value as of the balance sheet date of dividends declared but unpaid on equity securities issued by the entity and outstanding. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

+ References

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 210.5-02.20)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section 45
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=121566466&loc=d3e6935-107765

+ Details

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

- Definition

Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 50
-Section 40
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=117329964&loc=d3e12355-112629

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 50
-Section 40
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=117329964&loc=d3e12317-112629

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585

+ Details

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

- Definition

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.

+ References

No definition available.

+ Details

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

- Definition

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.

+ References

+ Details

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

- Definition

The amount of cash paid for deposits on goods and services during the period; excludes time deposits and deposits with other institutions, which pertain to financial service entities.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 17
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3367-108585

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 17
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3367-108585

+ Details

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

- Definition

The cash inflow from the sale of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3179-108585

+ Details

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

- Definition

Amount of cash and cash equivalents restricted as to withdrawal or usage, classified as current. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section 45
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121566466&loc=d3e6676-107765

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3044-108585

Reference 3: 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(1))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=121583591&loc=SL98516268-108586

+ Details

Name:	us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_SecuredDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongLivedAssetsHeldForSaleByAssetTypeAxis=gnk_GencoLorraineMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=gnk_SeniorSecured450MillionCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=gnk_TermLoan150MillionFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=gnk_Revolving300MillionCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongLivedAssetsHeldForSaleByAssetTypeAxis=gnk_BalticWindMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongLivedAssetsHeldForSaleByAssetTypeAxis=gnk_BalticBreezeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementScenarioAxis=srt_ScenarioForecastMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

Name:	us-gaap_LongLivedAssetsHeldForSaleByAssetTypeAxis=gnk_GencoProvenceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=gnk_AgreementToPurchaseThreeUltramaxVesselsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=gnk_AgreementToPurchase2017UltramaxVesselsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=gnk_AgreementToPurchase2014UltramaxVesselMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

SUBSEQUENT EVENTS (Details) $ / shares in Units, $ in Thousands									3 Months Ended						6 Months Ended
	Aug. 04, 2021 USD ($) $ / shares	Aug. 03, 2021 USD ($)	Jul. 26, 2021 USD ($)	Jul. 13, 2021 USD ($)	Jul. 06, 2021 USD ($)	Jul. 02, 2021 USD ($) item	Jun. 05, 2020	Jun. 04, 2020	Dec. 31, 2021 USD ($)	Sep. 30, 2021 USD ($)	Jun. 30, 2021 USD ($) $ / shares	Mar. 31, 2021 $ / shares	Jun. 30, 2020 $ / shares	Mar. 31, 2020 $ / shares	Jun. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)
Subsequent Events
Dividends declared per share of common stock \| $ / shares											$ 0.05	$ 0.02	$ 0.02	$ 0.175
Restricted cash, current											$ 44,606				$ 44,606	$ 35,492
Secured Debt \| $495 Million Credit Facility
Subsequent Events
Maximum borrowing capacity											495,000				495,000
Restricted cash, current											$ 44,606				$ 44,606	$ 35,492
Period for which sales proceeds from vessels will remain as restricted cash															360 days
Collateral vessel replacement period							360 days	180 days							360 days
Subsequent Event
Subsequent Events
Dividends declared per share of common stock \| $ / shares	$ 0.10
Aggregate amount of dividend	$ 4,200
Subsequent Event \| Genco Lorraine
Subsequent Events
Sale of assets					$ 7,950
Broker commission (as a percent)					2.50%
Subsequent Event \| $450 Million Credit Facility
Subsequent Events
Maximum borrowing capacity		$ 450,000
Term of facilities		5 years
Subsequent Event \| $150 Term Loan Million Facility
Subsequent Events
Maximum borrowing capacity		$ 150,000
Subsequent Event \| $300 Million Revolving Credit Facility
Subsequent Events
Maximum borrowing capacity		$ 300,000
Subsequent Event \| Secured Debt \| $495 Million Credit Facility \| Genco Lorraine
Subsequent Events
Restricted cash, current					$ 4,144
Period for which sales proceeds from vessels will remain as restricted cash					360 days
Collateral vessel replacement period					360 days
Subsequent Event \| Secured Debt \| $495 Million Credit Facility \| Baltic Wind
Subsequent Events
Vessel sale proceeds utilized as a loan repayment						$ 4,575
Subsequent Event \| Secured Debt \| $495 Million Credit Facility \| Baltic Breeze
Subsequent Events
Vessel sale proceeds utilized as a loan repayment			$ 4,797
Subsequent Event \| Forecast \| Minimum
Subsequent Events
Loss on debt extinguishment										$ 4,000
Subsequent Event \| Forecast \| Maximum
Subsequent Events
Loss on debt extinguishment										$ 5,000
Subsequent Event \| Forecast \| Genco Provence
Subsequent Events
Sale of assets									$ 13,250
Broker commission (as a percent)									2.50%
Subsequent Event \| Agreement To Purchase Ultramax Vessels
Subsequent Events
Payments for vessel deposits				$ 14,200
Subsequent Event \| Agreement To Purchase 2017 Ultramax Vessels
Subsequent Events
Number of vessels purchased \| item						2
Capacity of vessels \| item						63,000
Purchase price per vessel						$ 24,563
Subsequent Event \| Agreement To Purchase 2014 Ultramax Vessel
Subsequent Events
Number of vessels purchased \| item						1
Capacity of vessels \| item						63,000
Purchase price per vessel						$ 21,875