Segment and Geographic Information Narrative (Details)	3 Months Ended	6 Months Ended			3 Months Ended	6 Months Ended
	Jun. 30, 2011 customers	Jun. 30, 2012 reportable_segments customers distribution_centers	Jun. 30, 2011 customers	Dec. 31, 2011 customers	Jun. 30, 2012 Couche-Tard [Member]	Jun. 30, 2012 Couche-Tard [Member]	Jun. 30, 2012 United States distribution_centers	Jun. 30, 2012 Canada distribution_centers
Segment Reporting Information [Line Items]
Number of distribution centers		27					23	4
Number of distribution facilities operated as a third party logistics provider		2
Number of consolidating warehouses							3
Number of reportable segments		2
Major customer percentage of net sales					12.90%	13.20%
Customers accounting for 10% or more of total net sales, number	0		0
Customers accounting for 10% or more of accounts receivable, number		0		0