Valuation and Qualifying Accounts (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation Allowances and Reserves, Balance, Beginning Balance	$ 17,484	$ 22,618	$ 23,679
Valuation Allowances and Reserves, Charged to Cost and Expense	13,539	3,689	4,825
Valuation Allowances and Reserves, Deductions	2,308	8,823	5,886
Valuation Allowances and Reserves, Balance, Ending Balance	$ 28,715	$ 17,484	$ 22,618