SCHEDULE II VALUATION AND QUALIFYING ACCOUNTS (Details) - Allowance for doubtful accounts - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Movement in valuation and qualifying accounts
Balance at Beginning of Period	$ 6,565	$ 7,885	$ 9,962
Charged to Costs and Expenses	4,533	2,196	818
Deductions	(3,383)	(3,516)	(2,895)
Balance at End of Period	$ 7,715	$ 6,565	$ 7,885