Vessel Revenue and Voyage Expenses, Revenue Recognition (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Revenue Recognition [Abstract]
Demurrage income	$ 0	$ 800	$ 819
Despatch expense	$ 0	$ 110	$ 133

Expense for payments made to the charterer by the vessel owner when loading or discharging time is faster than the stipulated time in the voyage charter agreements.

No definition available.

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