SEGMENT INFORMATION (Physical Location and Values of Long-Lived Assets) (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	$ 164,749	$ 169,533
Belarus
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	72,805	73,988
Ukraine
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	28,621	30,980
United States
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	15,643	15,718
Russia
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	13,739	15,036
India
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	7,182	7,079
Poland
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	5,610	5,434
Hungary
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	4,840	5,365
Spain
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	2,670	2,799
China
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	2,409	2,722
Mexico
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	2,396	2,419
Other
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	$ 8,834	$ 7,993