Share-Based Compensation - Summary of Company's Share-Based Compensation Activity and Related Information (Parenthetical) (Detail) (USD $)	12 Months Ended
Dec. 31, 2012 Y
Share Based Compensation [Line Items]
Exercise prices for options and SARs outstanding, minimum	$ 37
Exercise prices for options and SARs outstanding, maximum	$ 63
Weighted-average remaining contractual life of the options and SARs outstanding	6

Share based compensation arrangement by share based payment award options and SARs outstanding weighted average remaining contractual term.

No definition available.

Name:	gpc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAndSarsOutstandingWeightedAverageRemainingContractualTerm
Namespace Prefix:	gpc_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration