Note 2 - Ownership Interests and Advances (Details Textual) $ in Millions	6 Months Ended
Jun. 30, 2022 USD ($)
Impairment of Other Method Securities	$ 2.5

The amount of impairment of other method securities.

No definition available.

Name:	sfe_ImpairmentOfOtherMethodSecurities
Namespace Prefix:	sfe_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration