Accounting Policies (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014 3 month LIBOR	Mar. 31, 2014 Recurring Fair value Cash flows approach	Dec. 31, 2013 Recurring Fair value Cash flows approach	Mar. 31, 2014 Recurring Significant Other Observable Inputs (Level 2) Cash flows approach	Dec. 31, 2013 Recurring Significant Other Observable Inputs (Level 2) Cash flows approach
Revenue Recognition
External freight billed to customers included in revenue	$ 6,500,000	$ 6,000,000
Fair Values of Financial Instruments
Interest rate swap liabilities				$ (1,304,000)	$ (1,533,000)	$ (1,304,000)	$ (1,533,000)
Variable rate basis			3 month LIBOR