Represents the accrual related to estimated customer claims.

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Balance Type:	credit
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- Definition

Represents the amount of amortization expense for drydocking.

+ References

No definition available.

+ Details

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

Represents the decrease in depreciation expense as a result of increase in estimated scrap value.

+ References

No definition available.

+ Details

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- Definition

Represents the depreciation of vessels.

+ References

No definition available.

+ Details

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- Definition

Represents the net (loss) income per share - basic and diluted (in dollars per share if no change to scrap value.

+ References

No definition available.

+ Details

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- Definition

Represents the increase (decrease) in basic and diluted net income (loss) per share.

+ References

No definition available.

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- Definition

Represents the period when the vessels are expected to be drydocked for overhaul repairs and maintenance.

+ References

No definition available.

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- Definition

Period of useful life of average scrap value of steel.

+ References

No definition available.

+ Details

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Data Type:	xbrli:durationItemType
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- Details

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- Definition

Represents the estimated scrap value of vessels.

+ References

No definition available.

+ Details

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Namespace Prefix:	gnk_
Data Type:	us-types:perUnitItemType
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- Definition

Represents the estimated useful life of vessels.

+ References

No definition available.

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- Details

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- Definition

A valuation allowance for trade and other receivables due to an Entity within one year (or the normal operating cycle, whichever is longer) that are expected to be uncollectible.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 4

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

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-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=35738203&loc=d3e5074-111524

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-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.4)

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

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- Definition

Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

+ References

+ Details

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- Definition

The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets.

+ References

+ Details

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- Definition

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

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-SubTopic 20

-Section 45

-Paragraph 1

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- Definition

Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

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Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

+ References

No definition available.

+ Details

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SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details 2) (USD $) In Thousands, except Per Share data, unless otherwise specified	1 Months Ended	2 Months Ended	3 Months Ended	6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended
	Jul. 31, 2014	Sep. 30, 2014	Dec. 31, 2014	Dec. 31, 2014	Dec. 31, 2014	Jul. 09, 2014	Dec. 31, 2013	Dec. 31, 2012
Due from charterers, net
Reserve against the due from charterers			$ 1,588	$ 1,588	1,588
Accrual related to estimated customer claims			662	662	662
Vessels, net
Estimated scrap value (in dollars per lightweight ton)				310gnk_VesselsEstimatedScrapValue
Estimated life of average scrap value of steel				15 years
Decrease in depreciation expense				1,540
Change to basic and diluted net loss per share as a result of decrease in depreciation				$ 0.03
Basic and diluted net loss per share if no change to estimated scrap value				$ (3.05)
Fixed assets, net
Depreciation and amortization				36,714
Asset Impairment Charges	0us-gaap_AssetImpairmentCharges	0us-gaap_AssetImpairmentCharges	0us-gaap_AssetImpairmentCharges
Deferred drydocking costs
Amortization expense for drydocking				330gnk_AmortizationExpenseOfDrydocking
Goodwill
Goodwill impairment				166,067us-gaap_GoodwillImpairmentLoss
Minimum
Deferred drydocking costs
Period for which vessels are required to be drydocked for major repairs and maintenance					30 months
Maximum
Deferred drydocking costs
Period for which vessels are required to be drydocked for major repairs and maintenance					60 months
Detail of Fixed Assets, Excluding Vessels
Fixed assets, net
Depreciation and amortization				119
Furniture and Fixtures
Fixed assets, net
Useful lives					5 years
Vessel
Vessels, net
Estimated useful life					25 years
Depreciation expense				36,265
Vessel \| Minimum
Fixed assets, net
Useful lives					2 years
Vessel \| Maximum
Fixed assets, net
Useful lives					15 years
Computer Equipment
Fixed assets, net
Useful lives					3 years
Predecessor
Due from charterers, net
Reserve against the due from charterers							632
Accrual related to estimated customer claims							536
Fixed assets, net
Depreciation and amortization						75,952	140,743	139,063
Asset Impairment Charges						0	0	0
Deferred drydocking costs
Amortization expense for drydocking						3,738	5,700	5,064
Goodwill
Goodwill						166,067
Predecessor \| Detail of Fixed Assets, Excluding Vessels
Fixed assets, net
Depreciation and amortization						458	1,481	888
Predecessor \| Vessel
Vessels, net
Depreciation expense						$ 71,756	$ 133,562	$ 133,111
Estimated scrap value (in dollars per lightweight ton)						245