PROPERTY PLANT AND EQUIPMENT (PPE BREAKOUT BY TYPE TABLE) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property Plant and Equipment Line Items
Property, plant and equipment, gross	$ 838,306	$ 801,183	$ 728,009
Less: Accumulated depreciation and amortization	(659,600)	(624,550)
Property, Plant and Equipment, Net, Total	178,706	176,633
Land And Building [Member]
Property Plant and Equipment Line Items
Property, plant and equipment, gross	32,944	32,942
Technology Equipment [Member]
Property Plant and Equipment Line Items
Property, plant and equipment, gross	474,415	447,260
Equipment [Member]
Property Plant and Equipment Line Items
Property, plant and equipment, gross	51,717	49,447
Furniture And Fixtures
Property Plant and Equipment Line Items
Property, plant and equipment, gross	85,149	85,191
Leasehold Improvements
Property Plant and Equipment Line Items
Property, plant and equipment, gross	193,823	186,083
Vehicles [Member]
Property Plant and Equipment Line Items
Property, plant and equipment, gross	$ 258	$ 260