Acquisitions (Details Textual) (USD $) In Millions, unless otherwise specified		6 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2012 Parent Company [Member]	Apr. 23, 2012 Parent Company [Member]	Jun. 30, 2012 Quaker City Motor Parts Co. [Member] Auto_parts_stores	May 01, 2012 Quaker City Motor Parts Co. [Member]
Acquisitions (Textual) [Abstract]
Company acquired Quaker City Motor Parts					$ 330
Annual revenues of Quaker City				300
Unsecured credit facility			200
Facility matures		2012-09-15
Existing credit facility		350
Expiry date		Dec. 18, 2012
Interest of credit facility		LIBOR plus 0.5%
Quaker City stores owned				140
Quaker City stores serviced				270
Name of the acquired entity				Quaker City Motor Parts Co.
Effective date of acquisition				2012/05/01
Date of initiation of credit line facility		2012/04/23
Amount outstanding under credit facility	0
Percentage of interest in addition to LIBOR		0.50%
Goodwill and other intangible assets acquired				$ 210