Represents the percentage of facility fee on the average daily outstanding principal amount of the loans outstanding.

No definition available.

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

- Definition

Represents the notice period for cancellation of line of credit.

+ References

No definition available.

+ Details

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

- Definition

The average effective interest rate during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- References

No definition available.

+ Details

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

- Definition

When presenting a range of interest rates, the highest effective rate for funds borrowed under the debt agreement as of the balance sheet date.

+ 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 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

When presenting a range of interest rates, the lowest effective rate for funds borrowed under the debt agreement as of the balance sheet date.

+ References

+ Details

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

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

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

- References

No definition available.

+ Details

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

- Definition

The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used.

+ References

No definition available.

+ Details

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

- Definition

Cash and equivalents whose use in whole or in part is restricted for the long-term, generally by contractual agreements or regulatory requirements.

+ 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 210.5-02.1)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Details

Name:	us-gaap_StatementScenarioAxis=us-gaap_PredecessorMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=gnk_CreditFacility2007Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

DEBT - Interest Rates (Details) - USD ($) $ in Thousands				1 Months Ended	6 Months Ended		12 Months Ended
DEBT - Interest Rates (Details) - USD ($) $ in Thousands	Jul. 09, 2014	Dec. 21, 2011	Sep. 21, 2005	Sep. 30, 2015	Dec. 31, 2014	Jul. 09, 2014	Dec. 31, 2016	Dec. 31, 2015
Interest rates on debt
Effective Interest Rate (as a percent)					3.60%		4.50%	3.65%
Range of Interest Rates, minimum (excluding impact of unused commitment fees) (as a percent)					2.73%		2.69%	2.69%
Range of Interest Rates, maximum (excluding impact of unused commitment fees) (as a percent)					3.76%		7.12%	6.73%
Letter of credit
Amount securitized and held as restricted cash in noncurrent assets							$ 27,426	$ 315
Predecessor
Interest rates on debt
Effective Interest Rate (as a percent)						4.19%
Range of Interest Rates, minimum (excluding impact of unused commitment fees) (as a percent)						3.15%
Range of Interest Rates, maximum (excluding impact of unused commitment fees) (as a percent)						5.15%
Letter of credit
Letter of credit
Fee on letter of credit (as a percent)				1.375%			1.375%	1.375%
Amount of letters outstanding							$ 300	$ 300
Amount securitized and held as restricted cash in noncurrent assets							$ 315	$ 315
Letter of credit \| Predecessor
Letter of credit
Fee on letter of credit (as a percent)			1.00%
Letter of credit \| Minimum
Letter of credit
Notice period for cancellation of line of credit							30 days
2007 Credit Facility \| Line of Credit Facility \| Predecessor
Letter of credit
Facility fee (as a percent)	1.00%	2.00%