Basis of Presentation (Details)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2012
Basis of Presentation [Abstract]
Number of weeks in fiscal period, minimum (in weeks)					52
Number of weeks in fiscal period, maximum (in weeks)					53
Number of weeks in second quarter (in weeks)	13	13
Number of weeks year to date (in weeks)			26	26