Name:	smp_LineOfCreditFacilityCancellationPeriod
Namespace Prefix:	smp_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Period of time at which borrowing available under credit facility automatically renew, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

Name:	smp_LineOfCreditFacilityRenewalPeriod
Namespace Prefix:	smp_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Threshold borrowing capacity limit to Tigger debt terms,

No definition available.

Name:	smp_ThresholdBorrowingCapacityLimit
Namespace Prefix:	smp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Threshold percentage of borrowing capacity to trigger different debt terms.

No definition available.

Name:	smp_ThresholdPercentageOfBorrowingCapacity
Namespace Prefix:	smp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

Carrying value as of the balance sheet date of payments made in excess of existing cash balances, which will be honored by the bank but reflected as a loan to the entity. Overdrafts generally have a very short time frame for correction or repayment and are therefore more similar to short-term bank financing than trade financing.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.20)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section 45
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481573/470-10-45-10

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

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

No definition available.

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

Name:	us-gaap_LineOfCreditFacilityAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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

Name:	us-gaap_DebtInstrumentAxis=smp_PolishOverdraftFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_VariableRateAxis=smp_WarsawInterbankOfferedRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_VariableRateAxis=smp_EuroInterbankOfferedRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: