The percentage points added to the reference rate to compute the variable rate on the debt instrument before amendment.

No definition available.

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

- Definition

The number of years the profile is based on for which the outstanding principle of this loan is amortized.

+ References

No definition available.

+ Details

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

- Definition

Represents the minimum cash balance per vessel required to be maintained for vessels owned under the credit facility.

+ References

No definition available.

+ Details

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

- Definition

Represents the minimum cash balance per vessel in its fleet required to be maintained by the entity.

+ References

No definition available.

+ Details

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

- Definition

Represents the number of draws made as of the reporting date.

+ References

No definition available.

+ Details

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Data Type:	xbrli:integerItemType
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- Definition

Represents the number of draws per vessel made as of the reporting date.

+ References

No definition available.

+ Details

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

- Definition

Represents the amount of upfront fee paid under the terms of credit facilities.

+ References

No definition available.

+ Details

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

- Definition

Represents the maturity term of the credit facility from the date of the first drawdown.

+ References

No definition available.

+ Details

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

Represents the amended maximum percentage of fleet wide liquidity covenant required.

+ References

No definition available.

+ Details

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

- Definition

Represents the ratio of total debt outstanding to value adjusted total assets (total assets adjustment for the difference between book value and market value of fleet vessels).

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
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- Definition

Represents the minimum period of working capital lines with remaining availability, in which the covenant of 50% of the required covenant of cash per vessel is satisfied.

+ References

No definition available.

+ Details

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

Number of unencumbered assets adding as additional collateral to cover the shortfall of fair value of mortgaged assets.

+ References

No definition available.

+ Details

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

Represents the number of vessels owned by each of the entity's wholly-owned ship-owning subsidiaries who act as guarantors under debt instrument.

+ References

No definition available.

+ Details

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

- Definition

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

+ References

No definition available.

+ Details

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

- Definition

Represents the number of vessels under option to purchase pursuant to the purchase agreement.

+ References

No definition available.

+ Details

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

- Definition

Amount of cash outflow for prepayment of amortization payment before due date.

+ References

No definition available.

+ Details

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

- Definition

Amount of payment made towards outstanding debt during the period.

+ References

No definition available.

+ Details

Name:	gnk_PrepaymentOfOutstandingDebt
Namespace Prefix:	gnk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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://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

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

- Definition

The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
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/presentationRef
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-Name Accounting Standards Codification
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- 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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations.

+ References

No definition available.

+ Details

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

- 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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-Name Accounting Standards Codification
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DEBT - $253M and $100M Term Loans (Details) $ in Thousands								1 Months Ended			6 Months Ended	12 Months Ended
DEBT - $253M and $100M Term Loans (Details) $ in Thousands	Mar. 29, 2016 USD ($)	Mar. 11, 2016 USD ($)	Jul. 29, 2015 USD ($)	Apr. 30, 2015 USD ($)	Jul. 09, 2014 USD ($)	Aug. 20, 2010 USD ($) tranche item	Aug. 12, 2010 USD ($) tranche item	Oct. 31, 2015 USD ($) item	Jul. 31, 2015 item	Apr. 30, 2015 USD ($) item	Mar. 31, 2011 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2010 USD ($)	Dec. 03, 2013 USD ($)	Aug. 30, 2013 USD ($)	Sep. 30, 2010 item
Line of Credit Facility
Minimum cash balance per vessel in the fleet				$ 750						$ 750						$ 750	$ 750
Secured Debt \| $253 Million Term Loan Facility
Line of Credit Facility
Maximum borrowing capacity						$ 253,000							$ 253,000	$ 253,000
Number of vessels acquired \| item						13
Number of drawdowns \| tranche						13
Number of drawdowns per vessel \| tranche						1
Commitment fee on unused daily average unutilized commitment (as a percent)						1.25%
Number of vessels owned by each of the entity's wholly-owned ship-owning subsidiaries who act as guarantors \| item						1
Paydown of debt					$ 5,075
Drawdowns during the period											$ 253,000				$ 253,000
Number of vessels delivered pursuant to the agreement \| item																		12
Number of unencumbered vessels adding as additional collateral to cover the shortfall of fair value \| item									5
Prepayment of the outstanding indebtedness		$ 5,075	$ 1,650					$ 5,075
Repayments of Secured Debt												$ 0	145,268	20,300
Long-term Debt												0	0
Payment of upfront fees				350
Secured Debt \| $253 Million Term Loan Facility \| LIBOR
Line of Credit Facility
Applicable margin over reference rate for interest payable, before increase (as a percent)						3.00%
Secured Debt \| $253 Million Term Loan Facility \| Minimum \| LIBOR
Line of Credit Facility
Reference rate						Three-month LIBOR
Secured Debt \| $253 Million Term Loan Facility \| Maximum
Line of Credit Facility
Reference rate						Six-month LIBOR
Secured Debt \| $100 Million Term Loan Facility
Line of Credit Facility
Maximum borrowing capacity							$ 100,000						100,000	100,000
Number of vessels acquired \| item							5
Number of drawdowns \| tranche							5
Number of drawdowns per vessel \| tranche							1
Reference rate							Three-month LIBOR
Commitment fee on unused daily average unutilized commitment (as a percent)							1.35%
Number of vessels owned by each of the entity's wholly-owned ship-owning subsidiaries who act as guarantors \| item							1
Paydown of debt					1,923
Drawdowns during the period							$ 20,000
Number of unencumbered vessels adding as additional collateral to cover the shortfall of fair value \| item								2		2
Repayments of Secured Debt												0	60,099	$ 7,692
Long-term Debt												$ 0	$ 0
Maturity term from the date of the first drawdown							7 years
Applicable margin over reference rate (as a percent)							3.00%
Profile for Amortization Period							13 years
Payment of upfront fees				$ 165
Prepayment of amortization payment before due date	$ 1,923
Secured Debt \| $100 Million Term Loan Facility \| Minimum
Line of Credit Facility
Reference rate							One-month LIBOR
Secured Debt \| $100 Million Term Loan Facility \| Maximum
Line of Credit Facility
Reference rate							Six-month LIBOR
Secured Debt \| $100 Million and $253 Million Term Loan Facilities
Line of Credit Facility
Minimum cash balance required per vessel owned					$ 750
Maximum total debt outstanding to value adjusted total assets ratio				70.00%
Maximum percentage of liquidity covenant amended				50.00%
Minimum period of available working capital lines				6 months
Secured Debt \| $100 Million and $253 Million Term Loan Facilities \| LIBOR
Line of Credit Facility
Applicable margin over reference rate for interest payable, before increase (as a percent)					3.00%
Applicable margin over reference rate (as a percent)					3.50%