Concentration Risk (Details) (Customer Concentration Risk [Member], Sales Revenue, Net [Member])	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Western Refining, Inc. [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	29.30%	25.50%
Kroger [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	24.30%	23.30%
Western Refining, Retail Business [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	22.50%	21.10%