SEC Schedule II 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	$ 143,511	$ 241,709	$ 84,818
Additions Charged Against Operations	(54,700)	(23,063)	216,784
Uncollectable Accounts Written-Off	(41,524)	(75,135)	(59,893)
Balance at End of Year	$ 47,287	$ 143,511	$ 241,709