Cash balances held in foreign currencies.

No definition available.

Name:	smp_ForeignCash
Namespace Prefix:	smp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

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- Definition

Represents the number of largest individual customers, including members of a marketing group.

+ References

No definition available.

+ Details

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Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of direct write-downs of accounts receivable charged against the allowance.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-Subparagraph (d)
-URI https://asc.fasb.org/extlink&oid=124255953&loc=SL82919249-210447

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The aggregate number of claims filed with the bankruptcy court.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 852
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=124433192&loc=d3e56015-112765

+ Details

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Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

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- Details

Name:	us-gaap_ConcentrationRiskByTypeAxis=us-gaap_CustomerConcentrationRiskMember
Namespace Prefix:
Data Type:	na
Balance Type:
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- Details

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Summary of Significant Accounting Policies, Concentrations of Credit Risk and Foreign Cash Balances (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($) Customer	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Concentration Risk [Abstract]
Number of customers who filed a petition \| Customer	1
Customer bankruptcy charge	$ 7,002	$ 0	$ 0
Foreign Cash Balances [Abstract]
Foreign cash balance	$ 18,500	$ 16,600
Customer Concentration Risk [Member]
Concentration Risk [Abstract]
Number of largest individual customers \| Customer	3
Selling, General and Administrative Expenses [Member]
Concentration Risk [Abstract]
Customer bankruptcy charge	$ 7,000