Summary Of Significant Accounting Policies (Summary Of Accrued Warranty Obligation) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Summary Of Significant Accounting Policies [Abstract]
Balance at the beginning of the year	$ 4,554	$ 3,813	$ 2,814
Warranty expense	5,856	6,427	4,629
Warranty payments	(5,797)	(5,686)	(3,630)
Balance at the end of the period	$ 4,613	$ 4,554	$ 3,813