Debt covenant unrestricted cash and cash equivalents minimum.

No definition available.

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Balance Type:	debit
Period Type:	instant

- Definition

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

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
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Period Type:	duration

- Definition

Represents the average age of collateral vessels for repayment of loan.

+ References

No definition available.

+ Details

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- Definition

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

+ References

No definition available.

+ Details

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- Definition

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.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
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- 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

Represents the maximum percentage of fair market value of aggregate vessels at delivery allowed under the credit facility.

+ References

No definition available.

+ Details

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- Definition

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

+ References

No definition available.

+ Details

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Data Type:	xbrli:pureItemType
Balance Type:	na
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- Definition

Minimum working capital required per terms of the credit facility.

+ References

No definition available.

+ Details

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

- Definition

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

+ References

No definition available.

+ Details

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Data Type:	xbrli:integerItemType
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Period Type:	instant

- Definition

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

+ References

No definition available.

+ Details

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

- Definition

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

+ References

No definition available.

+ Details

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

- Definition

The value of loan when the average age of the vessels serving as collateral from time to time reaches a specified period, following an initial non-amortization period and all additional debt covenants are met.

+ References

No definition available.

+ Details

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

- 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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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- 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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- 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

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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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- 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.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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Balance Type:	credit
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- Definition

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

+ References

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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- Definition

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

+ References

+ Details

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- 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.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
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- References

No definition available.

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- Definition

Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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- Definition

Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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- Definition

Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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- Definition

Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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- Definition

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.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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- Definition

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

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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DEBT - $108 Million Credit Facility (Details) $ in Thousands			3 Months Ended	12 Months Ended
	Nov. 05, 2019 USD ($)	Aug. 14, 2018 USD ($) item	Sep. 30, 2018 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Jul. 12, 2018 item	Jun. 06, 2018 item
Repayment of the outstanding debt
Total debt				$ 495,824	$ 551,420
Agreement To Purchase Ultramax And Capesize Vessels
Line of Credit Facility
Number of vessels committed to be acquired under purchase agreement \| item								4
Agreement to Purchase Capesize Drybulk Vessels
Line of Credit Facility
Number of vessels committed to be acquired under purchase agreement \| item							2	2
Agreement To Purchase Ultramax Drybulk Vessels
Line of Credit Facility
Number of vessels committed to be acquired under purchase agreement \| item								2
Secured Debt \| $108 Million Credit Facility
Line of Credit Facility
Term of facilities		5 years
Maximum borrowing capacity		$ 108,000		108,000	108,000
Proceeds from credit facility			$ 108,000		108,000
Number of vessels to serve as collateral under debt agreement \| item		6
Maximum facility amount of fair market value of aggregate vessels at delivery (as a percent)			45.00%
Remaining borrowing capacity				0
Repayment of secured debt				6,320	1,580	$ 0
Long-term debt				98,648	104,571
Repaid value of loan when certain debt terms are met		$ 0
Average age of collateral vessels for repayment of loan		20 years
Amount of repayment per quarter		$ 1,580
Percentage limit of consolidated net income for which dividends can be paid	50.00%
Debt covenant to pay dividends or repurchase stock - Total cash and cash equivalents to total indebtedness (as a percent)	18.75%
Key covenant - Unrestricted cash and cash equivalents minimum		$ 30,000
Key covenant – Percentage of unrestricted cash to total indebtedness		7.50%
Minimum working capital required		$ 0
Maximum total indebtedness to total capitalization (as a ratio)		0.70
Repayment of the outstanding debt
2020				6,320
2021				6,320
2022				6,320
2023				81,140
Total debt				$ 100,100	$ 106,420
Secured Debt \| $108 Million Credit Facility \| LIBOR
Line of Credit Facility
Reference rate		LIBOR
Secured Debt \| $108 Million Credit Facility \| LIBOR \| Through September 30, 2019
Line of Credit Facility
Applicable margin over reference rate (as a percent)		2.50%
Secured Debt \| $108 Million Credit Facility \| Agreement To Purchase Ultramax And Capesize Vessels
Line of Credit Facility
Number of vessels committed to be acquired under purchase agreement \| item		6
Secured Debt \| $108 Million Credit Facility \| Agreement to Purchase Capesize Drybulk Vessels
Line of Credit Facility
Number of vessels committed to be acquired under purchase agreement \| item		4
Secured Debt \| $108 Million Credit Facility \| Agreement To Purchase Ultramax Drybulk Vessels
Line of Credit Facility
Number of vessels committed to be acquired under purchase agreement \| item		2
Secured Debt \| Minimum \| $108 Million Credit Facility
Line of Credit Facility
Debt covenant to pay dividends or repurchase stock - Total cash and cash equivalents	$ 100,000
Collateral security maintenance test (as a percent)		135.00%
Secured Debt \| Minimum \| $108 Million Credit Facility \| LIBOR \| Period After September 30, 2019
Line of Credit Facility
Applicable margin over reference rate (as a percent)		2.25%
Secured Debt \| Maximum \| $108 Million Credit Facility
Line of Credit Facility
Collateral security maintenance test (as a percent)	200.00%
Secured Debt \| Maximum \| $108 Million Credit Facility \| LIBOR \| Period After September 30, 2019
Line of Credit Facility
Applicable margin over reference rate (as a percent)		2.75%