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Amount, after accumulated amortization, of financial liabilities issuance costs classified as noncurrent. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

No definition available.

Name:	ctrm_DeferredFinanceCostsNoncurrentNetFinancialLiabilities
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Data Type:	xbrli:monetaryItemType
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Amount, after accumulated amortization, of deferred financing liabilities. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

No definition available.

Name:	ctrm_DeferredFinancingLiabilitiesCostsNet
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Data Type:	xbrli:monetaryItemType
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Amount, after deduction of unamortized premium (discount) and financial liabilities.

No definition available.

Name:	ctrm_FinancialLiabilities
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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- References

No definition available.

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Data Type:	xbrli:stringItemType
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- References

No definition available.

Name:	ctrm_FinancialLiabilitiesByCurrentAndNoncurrentAbstract
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Data Type:	xbrli:stringItemType
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Amount, before unamortized (discount) premium and debt issuance costs, of financial liabilities. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

No definition available.

Name:	ctrm_FinancialLiabilitiesCarryingAmount
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount, before unamortized (discount) premium and debt issuance costs, of financial liabilities classified as current.

No definition available.

Name:	ctrm_FinancialLiabilitiesGrossCurrent
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Data Type:	xbrli:monetaryItemType
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Amount, before unamortized (discount) premium and debt issuance costs, of financial liabilities classified as noncurrent.

No definition available.

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Data Type:	xbrli:monetaryItemType
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Amount of long-term debt classified as other, payable within one year or the operating cycle, if longer.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(20))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
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-Publisher FASB
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount of long-term debt classified as other, payable after one year or the operating cycle, if longer.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-SubTopic 10
-Topic 210
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-04(13)(a)(4))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479170/946-210-S99-1