Name:	gnk_OtherAssetsLineItems
Namespace Prefix:	gnk_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Carrying amount of accumulated amortization of long-term deferred finance costs capitalized at the end of the reporting period.

+ 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 210.5-02.17)

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

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 17

-Article 5

+ Details

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

- Definition

Amount of noncash expense included in interest expense to issue debt and obtain financing associated with the related debt instruments. Alternate captions include noncash interest expense.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.8)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 8

-Article 5

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph 8

-Article 9

+ Details

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

- Definition

Gross amount, as of the balance sheet date, of capitalized costs associated with the issuance of debt instruments (for example, legal, accounting, underwriting, printing, and registration costs) that will be charged against earnings in periods after one year or beyond the normal operating cycle, if longer, over the life of the long-term debt instruments to which such costs pertain.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 45

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28555-108399

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 210.5-02.17)

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

+ Details

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

- Definition

Net amount of long-term deferred finance costs capitalized at the end of the reporting period.

+ References

+ Details

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

- 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

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

+ Details

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

DEFERRED FINANCING COSTS (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended			3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013	Jun. 30, 2014 2010 Notes	Jun. 30, 2013 2010 Notes	Jun. 30, 2014 2010 Notes	Jun. 30, 2013 2010 Notes	Dec. 31, 2013 2010 Notes	Jun. 30, 2014 2007 Credit Facility	Dec. 31, 2013 2007 Credit Facility	Jun. 30, 2014 $100 Million Term Loan Facility	Mar. 31, 2014 $100 Million Term Loan Facility	Dec. 31, 2013 $100 Million Term Loan Facility	Aug. 12, 2010 $100 Million Term Loan Facility	Jun. 30, 2014 $253 Million Term Loan Facility	Mar. 31, 2014 $253 Million Term Loan Facility	Dec. 31, 2013 $253 Million Term Loan Facility	Aug. 20, 2010 $253 Million Term Loan Facility	Jun. 30, 2014 2010 Baltic Trading Credit Facility	Dec. 31, 2013 2010 Baltic Trading Credit Facility	Aug. 29, 2013 2010 Baltic Trading Credit Facility	Nov. 30, 2010 2010 Baltic Trading Credit Facility	Apr. 16, 2010 2010 Baltic Trading Credit Facility	Jun. 30, 2014 Baltic Trading $22 Million Term Loan Facility	Dec. 31, 2013 Baltic Trading $22 Million Term Loan Facility	Jun. 30, 2014 Baltic Trading $44 Million Term Loan Facility	Dec. 31, 2013 Baltic Trading $44 Million Term Loan Facility
Other assets, net
Maximum borrowing capacity											$ 1,055,912		$ 100,000	$ 100,000	$ 100,000	$ 100,000	$ 253,000	$ 253,000	$ 253,000	$ 253,000			$ 110,000	$ 150,000	$ 100,000	$ 22,000	$ 22,000	$ 44,000	$ 44,000
Total deferred financing costs	44,572		44,572		44,290	3,637		3,637		3,637	29,568	29,568	1,857		1,783		4,884		4,708		3,339	3,339				529	518	758	737
Less: accumulated amortization	26,570		26,570		22,279
Total	18,002		18,002		22,011
Amortization of deferred financing costs	$ 2,071	$ 1,856	$ 4,291	$ 3,691		$ 39	$ 179	$ 216	$ 356