Name:	ctrm_RelatedPartyTransactionDueFromToRelatedPartiesCurrentAbstract
Namespace Prefix:	ctrm_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Fixed daily fee charged by a related party to provide a wide range of shipping services such as crew management, technical management, operational employment management, insurance arrangements, provisioning, bunkering, accounting services, general administration and audit support.

No definition available.

Name:	ctrm_RelatedPartyTransactionFixedDailyFee
Namespace Prefix:	ctrm_
Data Type:	srt-types:perUnitItemType
Balance Type:	na
Period Type:	duration

Amount of working capital guaranteed deposits paid to the related party.

No definition available.

Name:	ctrm_RelatedPartyTransactionWorkingCapitalGuaranteeDeposits
Namespace Prefix:	ctrm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of liabilities classified as other, due within one year or the normal operating cycle, if longer.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 852
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481372/852-10-55-10

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.20)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

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

Amount, after allowance, of receivables classified as other, due within one year or the operating cycle, if longer.

No definition available.

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

Name:	srt_CounterpartyNameAxis=ctrm_PavimarSAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RelatedPartyTransactionAxis=ctrm_TechnicalShipmanagementAgreementsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RelatedPartyTransactionAxis=ctrm_SubcontractedManagementAgreementsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: