The number of periodic payment installments in which the debt is to be repaid.

No definition available.

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Namespace Prefix:	ctrm_
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Period Type:	duration

- Definition

The number of tranches in which the debt instrument was drawn down.

+ References

No definition available.

+ Details

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- Definition

Number of the Company's ship-owning subsidiaries that entered into a senior secured term loan facility.

+ References

No definition available.

+ Details

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Namespace Prefix:	ctrm_
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- Definition

Face (par) amount of debt instrument at time of issuance.

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+ Details

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

- Definition

Description of the frequency of periodic payments (monthly, quarterly, annual).

+ References

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- Definition

Date when the debt instrument is scheduled to be fully repaid, in YYYY-MM-DD format.

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+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Amount of the required periodic payments including both interest and principal payments.

+ References

+ Details

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

- Definition

Amount of payment greater than the preceding installment payments to be paid at final maturity date of debt.

+ References

No definition available.

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
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- References

No definition available.

+ Details

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- Definition

The cash outflow to repay long-term debt that is wholly or partially secured by collateral. Excludes repayments of tax exempt secured debt.

+ References

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Balance Type:	credit
Period Type:	duration

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Long-Term Debt, $11.0 Million Term Loan Facility (Details)			12 Months Ended
	Dec. 06, 2019 USD ($)	Dec. 02, 2019 Tranche	Dec. 31, 2021 USD ($) Installment	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Nov. 22, 2019 USD ($) Subsidiary
Long-Term Debt [Abstract]
Repayment of loan			$ 6,878,500	$ 2,050,000	$ 0
$11.0 Million Term Loan Facility [Member]
Long-Term Debt [Abstract]
Number of ship-owning subsidiaries entering into term loan facility \| Subsidiary						2
Face amount			$ 11,000,000.0			$ 11,000,000.0
Number of tranches drawn \| Tranche		2
Term of loan			5 years
Number of payment installments \| Installment			20
Frequency of periodic payment			quarterly
Installment payment			$ 400,000
Balloon installment payable at maturity			$ 3,000,000.0
Maturity date			Dec. 02, 2024
$7.5 Million Bridge Loan [Member]
Long-Term Debt [Abstract]
Face amount	$ 7,500,000				$ 7,500,000
Repayment of loan	$ 7,500,000