Share Repurchase Program (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2024	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Feb. 23, 2022
Share Repurchase Program
Share Repurchase Program	$ 200,000	$ 200,000			$ 50,000
Number of common shares purchased during period under the program	0	0	74,213
Acquisition of treasury stock excluding excise tax			$ 5,240
Treasury stock shares repurchased cumulative	3,215,690	3,215,690
Treasury stock repurchased, at cost				$ 155,240

Number of previously issued common shares repurchased by the issuing entity and held in treasury for possible reissue/

No definition available.

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- Definition

Amount allocated to previously issued common shares repurchased by the issuing entity and held in treasury for future reissue.

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No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents the number of common shares that were repurchased during the period. Recorded using the cost method.

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No definition available.

+ Details

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Namespace Prefix:	saft_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Equity impact of the cost of common and preferred stock that were repurchased during the period excluding excise tax. Recorded using the cost method.

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No definition available.

+ Details

Name:	saft_TreasuryStockValueAcquiredCostMethodExcludingExciseTax
Namespace Prefix:	saft_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- References

No definition available.

+ Details

Name:	srt_ShareRepurchaseProgramAbstract
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Data Type:	xbrli:stringItemType
Balance Type:	na
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- Definition

Amount authorized for purchase of share under share repurchase plan. Includes, but is not limited to, repurchase of stock and unit of ownership.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 505
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481520/505-30-50-4

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant