EQUIPMENT AND PROPERTY (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Net equipment and property	$ 136,885	$ 134,088
Depreciation expense	30,364	27,381	$ 24,725
Foreign Countries [Member]
Property, Plant and Equipment [Line Items]
Net equipment and property	7,600	4,900
Building [Member]
Property, Plant and Equipment [Line Items]
Gross equipment and property	53,339	51,023
Equipment [Member]
Property, Plant and Equipment [Line Items]
Gross equipment and property	103,429	91,430
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Gross equipment and property	18,476	17,672
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Gross equipment and property	177,441	163,220
Plant and Equipment [Member]
Property, Plant and Equipment [Line Items]
Gross equipment and property	352,685	323,345
Less--Accumulated Depreciation	(240,320)	(213,809)
Net equipment and property	112,365	109,536
Land [Member]
Property, Plant and Equipment [Line Items]
Gross equipment and property	$ 24,520	$ 24,552