Segment Reporting (Details 3) (USD $)	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2013 Alliance and Exxon Mobil	Feb. 28, 2013 Basin Transload	Feb. 01, 2013 Basin Transload	Feb. 15, 2013 Cascade Kelly	Feb. 28, 2013 Cascade Kelly and Basin Transload	Feb. 15, 2013 Cascade Kelly and Basin Transload	Jun. 30, 2013 Gasoline Distribution and Station Operations segment Alliance and Exxon Mobil	Jun. 30, 2013 Wholesale Segment Basin Transload	Feb. 28, 2013 Wholesale Segment Basin Transload	Jun. 30, 2013 Wholesale Segment Cascade Kelly	Jun. 30, 2013 Wholesale Segment Cascade Kelly and Basin Transload	Feb. 28, 2013 Wholesale Segment Cascade Kelly and Basin Transload
Segment Assets
Assets including goodwill acquired in connection with acquisition			$ 627,600,000				$ 229,500,000
Property and equipment					28,016,000	45,100,000		73,100,000	465,800,000		28,000,000			73,100,000
Net book value of assets	$ 787,717,000	$ 712,322,000							$ 453,000,000	$ 26,000,000		$ 43,200,000	$ 69,200,000
Percentage of membership interests acquired				60.00%	60.00%	100.00%