SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS (Details) - Allowance for doubtful accounts - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Deduction from asset accounts:
Balance at Beginning of Period	$ 1,864	$ 1,850	$ 1,714
Charged to Expense	(462)	282	243
Accounts Written Off	(398)	(268)	(107)
Balance at End of Period	$ 1,004	$ 1,864	$ 1,850