Represents the minimum cash required per vessel mortgaged under this facility.

No definition available.

Name:	gnk_LineOfCreditFacilityCovenantCashAndCashEquivalentAndRemainingBorrowingCapacityForWorkingCapitalPerVesselRequiredToBeMaintained
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Balance Type:	debit
Period Type:	instant

- Definition

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.

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

Amount of fixed amortization payment for the first two years.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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- Definition

The maximum percentage of the value of the collateral as compared to the loan amount outstanding which requires prepayment of the line of credit using excess cash flows.

+ References

No definition available.

+ Details

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- Definition

Represents the number of collateral vessels, in which the loan is to be prepaid from earnings received from operations after deduction of costs, fees, expenses, interest, and fixed principal repayments under the facility; operating expenses relating to the vessels; and the Borrowers' pro rata share of general and administrative expenses based on the number of vessels they own.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Represents the line of credit period without amortization, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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

- Definition

The amount of loan repayment requirement to have the ability to pay dividends after December 31, 2018.

+ References

No definition available.

+ Details

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

- Definition

Number of Entities owned or controlled by the company.

+ References

No definition available.

+ Details

Name:	gnk_NumberOfWhollyOwnedSubsidiaries
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Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.

+ References

No definition available.

+ Details

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

- Definition

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.

+ References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of the required periodic payments of both interest and principal.

+ References

+ Details

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

- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

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

- Definition

Amount of cash inflow from contractual arrangement with the lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

+ References

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Balance Type:	debit
Period Type:	duration

- Definition

Amount of cash outflow for payment of an obligation from a lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

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Balance Type:	credit
Period Type:	duration

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DEBT - $98M Credit Facility (Details) - Line of Credit Facility - $98 Million Credit Facility			12 Months Ended
	Nov. 10, 2015 USD ($)	Nov. 04, 2015 USD ($) item	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Nov. 15, 2016 USD ($)
Line of Credit Facility
Number of wholly owned subsidiaries		13
Maximum borrowing capacity		$ 98,000,000		$ 98,000,000	$ 98,000,000	$ 98,000,000
Drawdowns during the period	$ 98,271,000
Repayment of line of credit facility			$ 0	93,939,000	$ 1,332,000
Fixed amortization payment for the first two years		$ 0
Period without fixed amortization schedule		2 years
Amount of periodic payment		$ 2,500,000
Maximum collateral required for prepayment of loan (as a percent)		182.00%
Number of collateral vessels \| item		13
Long-term debt			$ 0	$ 0
Minimum cash required to be maintained by each collateralized vessel						$ 750,000
Collateral security maintenance test (as a percent)						140.00%
LIBOR
Line of Credit Facility
Reference rate		three-month LIBOR
Applicable margin over reference rate for interest payable		6.125%
Minimum
Line of Credit Facility
Loan repayment requirement to have the ability to pay dividends after December 31, 2018		$ 25,000,000