Commitments and Contingent Liabilities (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Commitments And Contingent Liabilities Details
Treated	$ 2,400	$ 2,400	$ 2,500
Untreated	3,100	2,700	2,900
Total Costs	$ 5,500	$ 5,100	$ 5,400