Amortization of Financing Costs, Next Twelve Months

No definition available.

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Balance Type:	debit
Period Type:	instant

- Definition

Amortization of Financing Costs, Remainder of Fiscal Year

+ References

No definition available.

+ Details

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- Definition

Amortization Of Financing Costs Year Five

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

Amortization Of Financing Costs Year Four

+ References

No definition available.

+ Details

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- Definition

Amortization Of Financing Costs Year Three

+ References

No definition available.

+ Details

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- Definition

Amortization Of Financing Costs Year Two

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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- Definition

Debt Instrument, Amortization Percentage of Periodic Payment

+ References

No definition available.

+ Details

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Namespace Prefix:	smp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Covenant, Leverage Ratio, Maximum

+ References

No definition available.

+ Details

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Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Covenant, Maximum, Debt To EBITDA Ratio

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Extension Term

+ References

No definition available.

+ Details

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Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Number of Extensions

+ References

No definition available.

+ Details

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

- Definition

Line of Credit Facility, Accordion Feature, Increase Limit

+ References

No definition available.

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Line of Credit Facility, Cancellation Period

+ References

No definition available.

+ Details

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- Definition

Line of Credit Facility, Threshold Borrowing Capacity Limit

+ References

No definition available.

+ Details

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

- Definition

Line of Credit Facility, Threshold Percentage of Borrowing Capacity

+ References

No definition available.

+ Details

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Data Type:	dtr-types:percentItemType
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- Definition

Amount of amortization expense attributable to debt issuance costs.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-SubTopic 10
-Name Accounting Standards Codification
-Section S99
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-Subparagraph (SX 210.5-03(8))
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- Definition

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.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(20))
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-Topic 470
-SubTopic 10
-Section 45
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481573/470-10-45-10

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Balance Type:	credit
Period Type:	instant

- Definition

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

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
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+ Details

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Period Type:	instant

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

Weighted average interest rate of debt outstanding.

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

Amount, before accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 835
-SubTopic 30
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-Paragraph 2
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-Section 50
-Paragraph 1
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- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
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-Topic 815
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-Section 50
-Paragraph 1A
-Subparagraph (d)
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-URI https://asc.fasb.org/1943274/2147480434/815-10-50-1A

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- Definition

Represents the portion of interest incurred in the period on debt arrangements that was charged against earnings, excluding amortization of debt discount (premium) and financing costs.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(8))
-Publisher FASB
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-Topic 470
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-Section 50
-Paragraph 1F
-Subparagraph (b)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1F

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

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

Name:	us-gaap_LettersOfCreditOutstandingAmount
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
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-Topic 210
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-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1

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-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16)(a)(2))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Average amount borrowed under the credit facility during the period.

+ References

No definition available.

+ Details

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Balance Type:	credit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (b)
-Publisher FASB
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-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
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-Subparagraph (a)
-Publisher FASB
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Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(f))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480678/235-10-S99-1

+ Details

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Period Type:	duration

- Definition

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.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22)(b))
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-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(19)(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

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Balance Type:	credit
Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the current portion of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(19))
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-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(13))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1

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- Definition

The carrying value as of the balance sheet date of the noncurrent portion of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
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-SubTopic 10
-Section 45
-Paragraph 14
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481573/470-10-45-14

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- Details

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Credit Facilities and Long-Term Debt - Narrative (Details) zł in Millions	9 Months Ended		12 Months Ended
	Sep. 30, 2024 USD ($) extension	Sep. 30, 2023 USD ($)	Dec. 31, 2023 USD ($)	Sep. 30, 2024 PLN (zł) extension	Jul. 31, 2024 USD ($)	Jun. 30, 2022 USD ($)
Line of Credit Facility [Line Items]
Line of credit, noncurrent	$ 140,000,000		$ 151,000,000
Borrowings under credit agreement			156,000,000
Line of credit, current			5,000,000
Outstanding amount	2,300,000		2,300,000
Debt issuance costs	5,100,000		1,600,000
Amortization of deferred financing cost	1,655,000	$ 370,000
Interest expense	1,300,000
Amortization of financing costs, remainder of 2024	100,000
Amortization of financing costs of 2025	500,000
Amortization of financing costs of 2026	500,000
Amortization of financing costs of 2026	500,000
Amortization of financing costs of 2027	500,000
Amortization of financing costs of 2028	300,000
Interest Rate Swap
Line of Credit Facility [Line Items]
Derivative, notional amount						$ 100,000,000
2024 Credit Agreement
Line of Credit Facility [Line Items]
Borrowings under credit agreement	140,000,000
2024 Credit Agreement \| Interest Rate Swap
Line of Credit Facility [Line Items]
Derivative, notional amount	$ 100,000,000
2024 Credit Agreement \| Line of Credit
Line of Credit Facility [Line Items]
Debt instrument, term	5 years
Leverage ratio	2.75			2.75
Debt, weighted average interest rate	5.00%			5.00%
2024 Credit Agreement \| Secured Debt \| Line of Credit
Line of Credit Facility [Line Items]
Debt instrument, number of extensions \| extension	2			2
Debt instrument, extension term	1 year			1 year
Accordion feature, increase limit	$ 168,000,000
Covenant, maximum, debt to EBITDA ratio	100.00%			100.00%
2024 Credit Agreement \| Revolving Credit Facility \| Line of Credit
Line of Credit Facility [Line Items]
Borrowing capacity	$ 750,000,000
2024 Credit Agreement \| Bridge Loan \| Line of Credit
Line of Credit Facility [Line Items]
Borrowing capacity	30,000,000
2024 Credit Agreement \| Letter of Credit \| Line of Credit
Line of Credit Facility [Line Items]
Borrowing capacity	$ 25,000,000
2024 Credit Agreement \| Minimum \| Base Rate \| Line of Credit
Line of Credit Facility [Line Items]
Variable rate	1.25%
2024 Credit Agreement \| Maximum \| Base Rate \| Line of Credit
Line of Credit Facility [Line Items]
Variable rate	2.25%
2024 Credit Agreement \| Debt Instrument, Redemption, Period One \| Secured Debt \| Line of Credit
Line of Credit Facility [Line Items]
Amortization percentage of periodic payment	1.25%
2024 Credit Agreement \| Debt Instrument, Redemption, Period Two \| Secured Debt \| Line of Credit
Line of Credit Facility [Line Items]
Amortization percentage of periodic payment	1.875%
2024 Credit Agreement \| Debt Instrument, Redemption, Period Three \| Secured Debt \| Line of Credit
Line of Credit Facility [Line Items]
Amortization percentage of periodic payment	2.50%
2024 Credit Agreement, Global Tranche \| Revolving Credit Facility \| Line of Credit
Line of Credit Facility [Line Items]
Borrowing capacity	$ 430,000,000
2024 Credit Agreement, Danish Tranche \| Secured Debt \| Line of Credit
Line of Credit Facility [Line Items]
Accordion feature, increase limit	5,000,000
2024 Credit Agreement, Danish Tranche \| Revolving Credit Facility \| Line of Credit
Line of Credit Facility [Line Items]
Borrowing capacity	10,000,000
Delayed Draw Term Loan Facility In US \| Secured Debt \| Line of Credit
Line of Credit Facility [Line Items]
Borrowing capacity	200,000,000
Euros Delayed Draw Term Loan Facility \| Secured Debt \| Line of Credit
Line of Credit Facility [Line Items]
Borrowing capacity	100,000,000
2022 Credit Agreement
Line of Credit Facility [Line Items]
Borrowings under credit agreement			$ 156,000,000
Debt, weighted average interest rate			5.00%
2022 Credit Agreement \| Interest Rate Swap
Line of Credit Facility [Line Items]
Derivative, notional amount			$ 100,000,000
2022 Credit Agreement \| Line of Credit
Line of Credit Facility [Line Items]
Debt, weighted average interest rate			5.00%
2022 Credit Agreement \| Secured Debt \| Line of Credit
Line of Credit Facility [Line Items]
Debt instrument, face amount					$ 125,000,000
Alternative Base Rate Loan \| Line of Credit
Line of Credit Facility [Line Items]
Average outstanding amount	800,000	$ 100,000	$ 100,000
Polish Overdraft Facility \| Line of Credit
Line of Credit Facility [Line Items]
Borrowing capacity	$ 7,500,000			zł 30
Threshold percentage of borrowing capacity	85.00%			85.00%
Threshold borrowing capacity limit	$ 6,400,000
Cancellation period	30 days
Bank overdrafts	$ 1,300,000		$ 0
Polish Overdraft Facility \| Warsaw Interbank Offered Rate \| Line of Credit
Line of Credit Facility [Line Items]
Variable rate	1.00%
Polish Overdraft Facility \| Euro Interbank Offered Rate \| Line of Credit
Line of Credit Facility [Line Items]
Variable rate	1.00%
Polish Overdraft Facility \| Mid-Point Fed Target Range Rate \| Line of Credit
Line of Credit Facility [Line Items]
Variable rate	1.25%