UNAUDITED INTERIM CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($)	6 Months Ended
Mar. 31, 2019	Mar. 31, 2018
REVENUES:
Address commissions	$ 81,204	$ 65,643

Address commissions represent discount (sales incentive) on services rendered by the Company and no identifiable benefit is received in exchange for the consideration provided to the charterer.

No definition available.

Name:	ctrm_AddressCommissions
Namespace Prefix:	ctrm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration