Allowances For Doubtful Accounts (Summary Of The Allowance For Doubtful Accounts) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Allowances For Doubtful Accounts [Abstract]
Balance, beginning of year	$ 3,090	$ 3,000	$ 440
Provision	23	15	2,557
Write-offs, net of recoveries	(706)	75	3
Balance, end of year	$ 2,407	$ 3,090	$ 3,000