Note 8 - Income Taxes - Schedule of Summary of Operating Loss Carryforwards (Details) $ in Thousands	Dec. 31, 2023 USD ($)
2024	$ 50,140
2025	17,408
2026	7,648
2027	15,100
2028 and thereafter	182,520
Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration	$ 272,816

Represent net operating loss carryforwards expiring in year five and thereafter.

No definition available.

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Period Type:	instant

- Definition

Represents net operating loss carryforwards expiring in year four.

+ References

No definition available.

+ Details

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Namespace Prefix:	sfe_
Data Type:	xbrli:monetaryItemType
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Period Type:	instant

- Definition

Represents net operating loss carryforwards expiring in year one.

+ References

No definition available.

+ Details

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Namespace Prefix:	sfe_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents net operating loss carryforwards expiring in year three.

+ References

No definition available.

+ Details

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Namespace Prefix:	sfe_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents net operating loss carryforwards expiring in year two.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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- Definition

Amount before allocation of valuation allowances of deferred tax asset attributable to deductible operating loss carryforwards that are subject to expiration dates.

+ References

No definition available.

+ Details

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