Basis of Presentation (Details)	Mar. 31, 2014
Basis of Presentation [Abstract]
Equity ownership in entities included in consolidated financial statements, minimum (in hundredths)	50.00%

Minimum equity ownership percentage in the entities included in the consolidated financial statements.

No definition available.

Name:	smp_EquityOwnershipInEntitiesIncludedInConsolidatedFinancialStatementsMinimum
Namespace Prefix:	smp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant