SCHEDULE II-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, 2011 Allowance for inventory obsolescence	Dec. 31, 2010 Allowance for inventory obsolescence	Dec. 31, 2009 Allowance for inventory obsolescence	Dec. 31, 2011 Allowance for doubtful accounts receivable	Dec. 31, 2010 Allowance for doubtful accounts receivable	Dec. 31, 2008 Allowance for doubtful accounts receivable
VALUATION AND QUALIFYING ACCOUNTS
Balance at Beginning of Year	$ 7,588	$ 6,662	$ 5,580	$ 7,541	$ 6,615	$ 5,533	$ 47	$ 47	$ 47
Additions Charged to Costs and Expenses	900	6,818	1,082	707	926	1,082	193	5,892
Deductions		(5,892)						(5,892)
Balance at End of Year	$ 8,488	$ 7,588	$ 6,662	$ 8,248	$ 7,541	$ 6,615	$ 240	$ 47	$ 47