Significant Customers, Geographic Areas, And Business Segments (Schedule Of Revenue By Geographic Area) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Revenue, Major Customer [Line Items]
Export sales	$ 41,644	$ 61,087
United States [Member]
Revenue, Major Customer [Line Items]
Export sales	6,165	9,009
Americas [Member]
Revenue, Major Customer [Line Items]
Export sales	1,511	1,739
Netherlands [Member]
Revenue, Major Customer [Line Items]
Export sales	4,920	5,402
Other Europe [Member]
Revenue, Major Customer [Line Items]
Export sales	7,435	9,562
China [Member]
Revenue, Major Customer [Line Items]
Export sales	8,356	14,898
Japan [Member]
Revenue, Major Customer [Line Items]
Export sales	6,403	11,616
Other Asia [Member]
Revenue, Major Customer [Line Items]
Export sales	6,273	7,850
Other [Member]
Revenue, Major Customer [Line Items]
Export sales	$ 581	$ 1,011