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 Disclosure [Line Items]
Balance at beginning of year	$ 4,708	$ 4,708	$ 2,598
Additions charged to expenses	2,234	1,375	2,723
Write-offs net of recoveries	(2,327)	(1,375)	(613)
Balance at end of year	4,615	4,708	4,708
Deferred Tax Asset Valuation Allowance [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of year	163	332	332
Additions charged to expenses	1,099
Deferred tax assets utilized		(169)
Balance at end of year	$ 1,262	$ 163	$ 332