FIXED ASSETS (Components of Fixed Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 93,147	$ 92,827
Accumulated depreciation	(61,598)	(60,184)
Property, plant and equipment, net, total	31,549	32,643
Furniture and fixtures [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	3,106	5,745
Computer hardware and software [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	69,865	69,973
Equipment [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	7,515	5,173
Leasehold improvements [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 12,661	$ 11,936