OPERATING SEGMENTS - Geographical Information of Long-Lived Assets Based on Physical Location (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	$ 64,294	$ 60,499
Belarus
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	44,724	44,879
Ukraine
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	5,091	4,487
Hungary
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	3,369	2,485
Russia
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	3,099	2,084
Russia
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	2,314	1,969
India
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	1,333	1,099
Poland
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	1,464	1,088
Other
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	$ 2,900	$ 2,408