Business Acquisitions - Additional Information (Detail) (Quaker City Motor Parts Co. [Member], USD $) In Millions, unless otherwise specified	1 Months Ended	9 Months Ended
May 01, 2012	Sep. 30, 2012 Auto_Parts_Stores
Quaker City Motor Parts Co. [Member]
Business Acquisition [Line Items]
Effective date of acquisition		May 01, 2012
Name of the acquired entity		Quaker City Motor Parts Co.
Company acquired Quaker City Motor Parts	$ 343
Annual revenues of Quaker City		300
Quaker City stores serviced		270
Quaker City stores owned		140
Goodwill and other intangible assets acquired		$ 220.0

Name of the acquired entity.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 50

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Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141R

-Paragraph 68

-Subparagraph a

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 51

-Subparagraph a

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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