Acquisitions (Details)	3 Months Ended	6 Months Ended
Jun. 30, 2013 stores	Jun. 30, 2012 stores	Jun. 30, 2013 stores	Jun. 30, 2012 stores
Business Combinations [Abstract]
Number of stores purchased	3	0	3	0

The number of businesses acquired by the entity during the period.

No definition available.

Name:	us-gaap_NumberOfBusinessesAcquired
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration