Valuation and Qualifying Accounts (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Allowance for Trade Receivables [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Valuation Allowances and Reserves, Balance	$ 358,713	$ 401,027	$ 332,541	$ 319,417
Valuation Allowances and Reserves, Charged to Cost and Expense	98,552	136,630	92,495
Valuation Allowances and Reserves, Adjustments	(140,866)	(68,144)	(79,371)
Valuation Allowance of Deferred Tax Assets [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Valuation Allowances and Reserves, Balance	18,232	18,418	22,594	25,233
Valuation Allowances and Reserves, Charged to Cost and Expense	1,881	(3,723)	(2,617)
Valuation Allowances and Reserves, Adjustments	$ (2,067)	$ (453)	$ (22)