The value of the cash award for compensation.

No definition available.

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

- Definition

Represents maximum aggregate exposure for employee and severance agreement.

+ References

No definition available.

+ Details

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

- Definition

Represents maximum aggregate shares exposure for employee and severance agreement.

+ References

No definition available.

+ Details

Name:	sfe_EmployeeAndSeveranceAgreementMaximumAggregateExposureShares
Namespace Prefix:	sfe_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents amount of payments under long-term incentive plan.

+ References

No definition available.

+ Details

Name:	sfe_LongTermIncentivePlanPayments
Namespace Prefix:	sfe_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents bonus pool percent for long-term incentive plan.

+ References

No definition available.

+ Details

Name:	sfe_LongtermIncentivePlanBonusPoolPercent
Namespace Prefix:	sfe_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Aggregate carrying value as of the balance sheet date of the liabilities for all deferred compensation arrangements. Represents currently earned compensation under compensation arrangements that is not actually paid until a later date.

+ References

No definition available.

+ Details

Name:	us-gaap_DeferredCompensationLiabilityCurrentAndNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The current carrying amount of the liability for the freestanding or embedded guarantor's obligations under the guarantee or each group of similar guarantees.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 460
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482425/460-10-50-4

+ Details

Name:	us-gaap_GuaranteeObligationsCurrentCarryingValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_TypeOfArrangementAxis=sfe_AmendedAndRestatedSafeguardScientificsTransactionBonusPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InvestmentTypeAxis=us-gaap_PrivateEquityFundsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Note 9 - Commitments and Contingencies (Details Textual) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022	Dec. 31, 2021
Long-term Incentive Plan, Payments	$ 0	$ 0	$ 0	$ 0
Deferred Compensation Liability, Current and Noncurrent, Total	0		0
Employee and Severance Agreement, Maximum Aggregate Exposure	1,000		$ 1,000
Employee and Severance Agreement, Maximum Aggregate Exposure, Shares (in shares)			187,500
Amended and Restated Safeguard Scientifics Transaction Bonus Plan [Member]
Compensation, Cash Award	0	$ 0	$ 0	$ 0
Minimum [Member]
Long-term Incentive Plan, Bonus Pool Percent						1.00%
Maximum [Member]
Long-term Incentive Plan, Bonus Pool Percent					1.30%
Private Equity Funds [Member]
Guarantor Obligations, Current Carrying Value	$ 3,800		$ 3,800