SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS AND RESERVES (Details) - Allowance for doubtful accounts - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Fiscal Period	$ 1,487	$ 1,246	$ 1,751
Charges to Costs and Expense	882	1,049	1,093
Deductions	(822)	(808)	(1,598)
Balance at End of Fiscal Period	$ 1,547	$ 1,487	$ 1,246