VALUATION AND QUALIFYING ACCOUNTS (Details) (Allowance for doubtful accounts receivable, USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Allowance for doubtful accounts receivable
Valuation and qualifying accounts
Balance at Beginning of Period	$ 2,086	$ 3,770	$ 3,128
Additions Charged to Costs and Expenses	998	808	1,754
Deductions	531	2,492	1,112
Balance at End of Period	$ 2,553	$ 2,086	$ 3,770