Accrued Liabilities (Schedule Of Product Warranty Liability) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Accrued Liabilities [Abstract]
Beginning Balance	$ 1,857	$ 1,253	$ 2,381
Provision for warranty expense	2,953	2,589	1,731
Warranty expired	(2,445)	(1,985)	(2,859)
Ending Balance	$ 2,365	$ 1,857	$ 1,253