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The number of installations of ballast water management systems (BWMS) expected to be concluded during the second fiscal year following current fiscal year.

No definition available.

Name:	ctrm_NumberOfInstallationsExpectedToBeConcludedYearTwo
Namespace Prefix:	ctrm_
Data Type:	xbrli:integerItemType
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Period Type:	instant

The number of vessels on which ballast water management systems (BWMS) were contracted to be installed.

No definition available.

Name:	ctrm_NumberOfVesselsOnWhichBallastWaterManagementSystemsWereContractedToBeInstalled
Namespace Prefix:	ctrm_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

The number of vessels on which ballast water management systems (BWMS) were in the process of being installed.

No definition available.

Name:	ctrm_NumberOfVesselsOnWhichBallastWaterManagementSystemsWereInProcessOfBeingInstalled
Namespace Prefix:	ctrm_
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The number of vessels on which ballast water management systems (BWMS) will be installed.

No definition available.

Name:	ctrm_NumberOfVesselsOnWhichBallastWaterManagementSystemsWillBeInstalled
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The number of vessels on which ballast water management systems (BWMS) were were completed and put into use.

No definition available.

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Namespace Prefix:	ctrm_
Data Type:	xbrli:integerItemType
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Foreign exchange rate used to translate amounts denominated in functional currency to reporting currency.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 830
-SubTopic 30
-Section S99
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=6897108&loc=SL6897125-166521

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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-SubTopic 30
-Section 50
-Paragraph 2
-URI https://asc.fasb.org/extlink&oid=6450520&loc=d3e32618-110901

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- References

No definition available.

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Amount of lease payments to be received by lessor for operating lease.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 50
-Paragraph 12
-URI https://asc.fasb.org/extlink&oid=124258985&loc=SL77919396-209981

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

Amount of lease payment to be received by lessor for operating lease in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
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- References

No definition available.

Name:	us-gaap_OtherCommitmentsAbstract
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Minimum amount to be expended to satisfy the terms of arrangements in which the entity has agreed to expend funds to procure goods or services, excluding long-term purchase commitments or unconditional purchase obligations.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(17))
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(19))
-URI https://asc.fasb.org/extlink&oid=126734703&loc=d3e572229-122910

Reference 3: 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(25))
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount of purchase arrangement to be paid in next fiscal year following current fiscal year. Includes, but is not limited to, recorded and unrecorded purchase obligations, long-term purchase commitment, and short-term purchase commitment. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

No definition available.

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

Amount of purchase arrangement to be paid in second fiscal year following current fiscal year. Includes, but is not limited to, recorded and unrecorded purchase obligations, long-term purchase commitment, and short-term purchase commitment. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

No definition available.

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

Amount of purchase arrangement to be paid in remainder of current fiscal year. Includes, but is not limited to, recorded and unrecorded purchase obligations, long-term purchase commitment, and short-term purchase commitment.

No definition available.