SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS AND RESERVES [Schedule] - VALUATION AND QUALIFYING ACCOUNTS AND RESERVES (Details) - Allowance for doubtful accounts - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
VALUATION AND QUALIFYING ACCOUNTS AND RESERVES
Balance at beginning of period	$ 967	$ 513	$ 1,088
Additions charged to income	3,431	575	282
Accounts receivable written off	(1,429)	(36)	(742)
Currency and Other Adjustments	(364)	(85)	(115)
Balance at end of period	$ 2,605	$ 967	$ 513