ACCOUNTS RECEIVABLE AND RELATED ALLOWANCE FOR DOUBTFUL ACCOUNTS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015
Accounts Receivable, Net [Abstract]
Accounts receivable				$ 94,309	$ 89,291
Allowance for doubtful accounts	$ (2,134)	$ (2,134)	$ (2,413)	(2,137)	(2,134)
Accounts receivable, net of allowance for doubtful accounts				$ 92,172	$ 87,157
Allowance for doubtful accounts
Allowance for doubtful accounts	2,134	2,449	2,413
Additions Charged to Costs and Expenses	(1,330)	(1,553)	(1,004)
Deduction From Reserves	(1,327)	(1,868)	(968)
Allowance for doubtful accounts	$ 2,137	$ 2,134	$ 2,449