SCHEDULE II VALUATION AND QUALIFYING ACCOUNTS AND RESERVES (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Allowance for doubtful accounts receivable and revenue adjustments
Changes in valuation and qualifying accounts and reserves
Balance at Beginning of Period	$ 5,957	$ 3,944	$ 3,470
Additions, Charged to Costs and Expenses	1,524	2,394	868
Additions, Charged to Other Accounts	26	2,667	1,640
Deductions	2,258	3,048	2,034
Balance at End of Period	5,249	5,957	3,944
Allowance for other accounts receivable
Changes in valuation and qualifying accounts and reserves
Balance at Beginning of Period	1,226	1,254	1,149
Additions, Charged to Costs and Expenses	108	(28)	105
Balance at End of Period	1,334	1,226	1,254
Allowance for deferred tax assets
Changes in valuation and qualifying accounts and reserves
Balance at Beginning of Period	5,644	2,455	3,013
Additions, Charged to Costs and Expenses	791	214	1,217
Additions, Charged to Other Accounts	47	3,971
Deductions	3,971	996	1,775
Balance at End of Period	$ 2,511	$ 5,644	$ 2,455