SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS AND RESERVES (Details) (Allowance for doubtful accounts, USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Allowance for doubtful accounts
Movement in Valuation Allowances and Reserves
Balance at Beginning of Period	$ 18,335	$ 16,792	$ 26,636
Additions Charged to Costs and Expenses (Income)	1,581	5,134	(1,263)
Deductions	3,545	3,591	8,581
Balance at End of Period	$ 16,371	$ 18,335	$ 16,792