Vessel Revenue and Voyage Expenses, Voyage Expenses from Time Charters (Details) - USD ($) $ in Thousands	6 Months Ended
Jun. 30, 2023	Jun. 30, 2022
Voyage Expenses [Abstract]
Voyage expenses	$ (1,308)	$ (2,646)
Time Charters [Member]
Voyage Expenses [Abstract]
Voyage expenses	$ (1,308)	$ (2,646)

Voyage Expenses consisting of port, canal and bunker expenses and commission costs that are incurred on time-charter and voyage-charter arrangements. Commissions are paid directly to brokers by the company.

No definition available.

Name:	ship_VoyageExpenses
Namespace Prefix:	ship_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration