Financial Instruments and Concentrations of Risk (Details Textual) (USD $)	12 Months Ended						12 Months Ended						1 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Unionized Employees Concentration Risk [Member] employees	Dec. 31, 2012 Unionized Employees Concentration Risk [Member] Outside Of United States [Member] employees	Dec. 31, 2012 Unionized Employees Concentration Risk [Member] Canada And Mexico [Member] employees	Dec. 31, 2012 Sales Revenue, Goods, Net [Member] Customer	Dec. 31, 2011 Sales Revenue, Goods, Net [Member] Customer	Dec. 31, 2010 Sales Revenue, Goods, Net [Member] Customer	Dec. 31, 2012 Accounts Receivable [Member] Customer Concentration Risk [Member] SemCrude [Member] Customer	Dec. 31, 2011 Accounts Receivable [Member] Customer Concentration Risk [Member] SemCrude [Member] Customer	Jan. 30, 2013 Subsequent Event [Member] Unionized Employees Concentration Risk [Member] Canada And Mexico [Member] employees	Mar. 31, 2012 Interest Rate Swap [Member]
Derivative, Gain (Loss) on Derivative, Net	$ 149,000	$ 2,153,000	$ (11,969,000)										$ 400,000
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net													$ 300,000
Number of customers							0	0	0	1	1
Percentage of accounts receivables										16.00%	16.00%
Number of employees				690	480	110
Number of employees with contracts expiring in collective bargaining agreements						60
Number of employees with contracts renewing collective bargaining agreements												50
Collective bargaining period	3 years