PROPERTY AND EQUIPMENT - Details of property and equipment (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 183,568	$ 186,255
Less: Accumulated depreciation	(77,976)	(78,146)
Property and equipment, net	105,592	108,109
Buildings and Land [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	1,584	1,693
Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	105,496	108,945
Computer and Communication Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	30,111	29,106
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	4,193	4,119
Vehicles [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	260	262
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	37,341	33,041
Construction in Process [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 4,583	$ 9,089