Represents the aggregate purchase price for vessels per agreement.

No definition available.

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Namespace Prefix:	gnk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents brokerage commission payable in percentage to the third party.

+ References

No definition available.

+ Details

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

- Definition

The debt covenant period for replacement of new vessel having an equal or greater appraised value if in compliance with collateral maintenance test.

+ References

No definition available.

+ Details

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Balance Type:	na
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- 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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Namespace Prefix:	gnk_
Data Type:	xbrli:integerItemType
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- Definition

Number of vessels sold during that period which did not serve as collateral under credit facilities.

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

Represents the period for which the net sale proceeds from sale of vessels will remain classified as restricted cash following the sale date if or until a replacement vessel or vessels meeting certain requirements are added as collateral under the facility.

+ References

No definition available.

+ Details

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- 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://fasb.org/us-gaap/role/ref/legacyRef
-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 cash inflow from the sale of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3179-108585

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Period Type:	duration

- Definition

Amount of cash and cash equivalents restricted as to withdrawal or usage, classified as current. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section 45
-Paragraph 1
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-SubTopic 10
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-Publisher FASB
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=98513485&loc=SL98516268-108586

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Period Type:	instant

VESSEL ACQUISITIONS AND DISPOSITIONS (Details) $ in Thousands											3 Months Ended	9 Months Ended	12 Months Ended
	Oct. 21, 2019 USD ($)	Oct. 10, 2019 USD ($)	Jan. 28, 2019 USD ($)	Dec. 26, 2018 USD ($)	Dec. 17, 2018 USD ($)	Dec. 05, 2018 USD ($)	Nov. 13, 2018 USD ($)	Oct. 16, 2018 USD ($)	Sep. 13, 2018 USD ($)	Aug. 07, 2018 USD ($)	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Dec. 31, 2018 USD ($) item	Nov. 05, 2019 USD ($)	Apr. 15, 2019 USD ($)	Feb. 28, 2019 USD ($)	Sep. 30, 2018 USD ($)	Aug. 14, 2018 USD ($) item	Jul. 12, 2018 USD ($) item	Jun. 06, 2018 USD ($) item	Dec. 31, 2017 USD ($)
VESSEL ACQUISITIONS
Restricted cash, current													$ 4,947								$ 7,234
Number of vessels sold which did not serve as collateral under credit facilities \| item													6
Secured Debt \| $495 Million Credit Facility
VESSEL ACQUISITIONS
Face amount of term loan facility												$ 495,000	$ 495,000		$ 495,000	$ 495,000	$ 495,000
Collateral vessel replacement period												180 days
Secured Debt \| $108 Million Credit Facility
VESSEL ACQUISITIONS
Face amount of term loan facility												$ 108,000	108,000				$ 108,000	$ 108,000
Secured Debt \| Subsequent Event \| $495 Million Credit Facility
VESSEL ACQUISITIONS
Face amount of term loan facility														$ 495,000
Secured Debt \| Subsequent Event \| $108 Million Credit Facility
VESSEL ACQUISITIONS
Face amount of term loan facility														$ 108,000
Agreement To Purchase Ultramax And Capesize Vessels
VESSEL ACQUISITIONS
Number of vessels committed to be acquired under purchase agreement \| item																				4
Aggregate purchase price for vessels																				$ 141,000
Agreement To Purchase Ultramax And Capesize Vessels \| Secured Debt \| $108 Million Credit Facility
VESSEL ACQUISITIONS
Number of vessels committed to be acquired under purchase agreement \| item																		6
Agreement to Purchase Capesize Drybulk Vessels
VESSEL ACQUISITIONS
Number of vessels committed to be acquired under purchase agreement \| item																			2	2
Aggregate purchase price for vessels																			$ 98,000
Agreement to Purchase Capesize Drybulk Vessels \| Secured Debt \| $108 Million Credit Facility
VESSEL ACQUISITIONS
Number of vessels committed to be acquired under purchase agreement \| item																		4
Agreement To Purchase Ultramax Drybulk Vessels
VESSEL ACQUISITIONS
Number of vessels committed to be acquired under purchase agreement \| item																				2
Agreement To Purchase Ultramax Drybulk Vessels \| Secured Debt \| $108 Million Credit Facility
VESSEL ACQUISITIONS
Number of vessels committed to be acquired under purchase agreement \| item																		2
Genco Vigour
VESSEL ACQUISITIONS
Sale of assets			$ 6,550
Broker commission (as a percent)			2.00%
Genco Knight
VESSEL ACQUISITIONS
Sale of assets				$ 6,200
Broker commission (as a percent)				3.00%
Genco Beauty
VESSEL ACQUISITIONS
Sale of assets					$ 6,560
Broker commission (as a percent)					3.00%
Genco Muse
VESSEL ACQUISITIONS
Sale of assets						$ 6,660
Broker commission (as a percent)						2.00%
Genco Cavalier
VESSEL ACQUISITIONS
Sale of assets								$ 10,000
Broker commission (as a percent)								2.50%
Genco Cavalier \| Secured Debt \| $495 Million Credit Facility
VESSEL ACQUISITIONS
Face amount of term loan facility								$ 495,000
Restricted cash, current													$ 4,947
Period for which sales proceeds from vessels will remain as restricted cash								180 days
Collateral vessel replacement period								180 days
Genco Surprise
VESSEL ACQUISITIONS
Sale of assets										$ 5,300
Broker commission (as a percent)										3.00%
Genco Progress
VESSEL ACQUISITIONS
Sale of assets									$ 5,600
Broker commission (as a percent)									3.00%
Genco Explorer
VESSEL ACQUISITIONS
Sale of assets							$ 5,600
Broker commission (as a percent)							3.00%
Genco Thunder \| Secured Debt \| $495 Million Credit Facility
VESSEL ACQUISITIONS
Face amount of term loan facility												495,000
Genco Thunder \| Forecast
VESSEL ACQUISITIONS
Sale of assets											$ 10,400
Broker commission (as a percent)											2.00%
Genco Champion \| Subsequent Event
VESSEL ACQUISITIONS
Sale of assets	$ 6,600
Broker commission (as a percent)	3.00%
Genco Champion \| Secured Debt \| $495 Million Credit Facility
VESSEL ACQUISITIONS
Face amount of term loan facility												495,000
Genco Champion \| Secured Debt \| Subsequent Event \| $495 Million Credit Facility
VESSEL ACQUISITIONS
Restricted cash, current	$ 4,101
Collateral vessel replacement period	180 days
Genco Challenger \| Subsequent Event
VESSEL ACQUISITIONS
Sale of assets		$ 5,250
Broker commission (as a percent)		2.00%
Genco Challenger \| Secured Debt \| $495 Million Credit Facility
VESSEL ACQUISITIONS
Face amount of term loan facility												$ 495,000
Genco Challenger \| Secured Debt \| Subsequent Event \| $495 Million Credit Facility
VESSEL ACQUISITIONS
Restricted cash, current		$ 3,381
Collateral vessel replacement period		180 days