SCHEDULE II VALUATION AND QUALIFYING ACCOUNTS (Details) (Allowance for doubtful accounts, USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Allowance for doubtful accounts
Movement in valuation and qualifying accounts
Balance at Beginning of Period	$ 7,885	$ 9,962	$ 12,575
Charged to Costs and Expenses	2,196	818	504
Deductions	(3,516)	(2,895)	(3,117)
Balance at End of Period	$ 6,565	$ 7,885	$ 9,962