SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS (Details) (Allowance for doubtful accounts deducted from accounts receivable in the balance sheet, USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Allowance for doubtful accounts deducted from accounts receivable in the balance sheet
Movement in valuation and qualifying accounts
Balance at Beginning of Period	$ 985	$ 1,232	$ 714
Additions Charged to Costs and Expenses	494	83	1,292
Deductions	(344)	(330)	(774)
Balance at End of Period	$ 1,135	$ 985	$ 1,232