SEC Schedule II Valuation and Qualifying Accounts (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Valuation And Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	$ 46,531	$ 140,780	$ 239,785
Additions Charged Against Operations	9,697	(56,995)	(23,893)
Uncollectable Accounts Written-Off	(15,389)	(37,254)	(75,112)
Balance at End of Year	$ 40,839	$ 46,531	$ 140,780