Valuation and Qualifying Accounts (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Allowances deducted from assets
Beginning Balance	$ 84,963	$ 75,933	$ 63,166
Charged to Costs and Expenses	1,570	9,030	12,767
Deductions	(86,533)
Ending Balance		84,963	75,933
Deferred tax assets [Member]
Allowances deducted from assets
Beginning Balance	84,963	75,933	63,166
Charged to Costs and Expenses	1,570	9,030	12,767
Deductions	(86,533)
Ending Balance		$ 84,963	$ 75,933