Valuation And Qualifying Accounts (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Valuation And Qualifying Accounts [Abstract]
Allowance for doubtful accounts, Balance at Beginning of Year	$ 1,755	[1]	$ 2,606	[1]	$ 4,057	[1]
Allowance for doubtful accounts, Additions	447	[1]	246	[1]	1,495	[1]
Allowance for doubtful accounts, Deductions	(596)	[1]	(1,097)	[1]	(2,946)	[1]
Allowance for doubtful accounts, Balance at End of Year	$ 1,606	[1]	$ 1,755	[1]	$ 2,606	[1]

[1] Deductions represent uncollectible accounts written off, net of recoveries and other adjustments.