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]
Balance at beginning of period	$ 248,622	$ 168,876	$ 162,975
Charges to costs and expenses	613,619	546,909	508,603
Acquisition of business		56,596
Write-off of uncollectible accounts	(608,836)	(523,759)	(502,702)
Balance at end of period	$ 253,405	$ 248,622	$ 168,876