SEGMENT AND GEOGRAPHICAL REPORTING, Adjustments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Adjustment for [Abstract]
B27 settlement	$ 0	$ 0	$ 7,348
Impairment expense	0	0	68,735
Amortization of intangibles	17,266	18,061	20,621
Total operating income (loss)	33,490	19,332	(27,916)
Interest expense	17,054	15,564	10,932
Other income, net	(456)	(5,906)	72
Income (loss) before income taxes	16,892	9,674	(38,920)
Identifiable assets at year end	639,083	602,052
Depreciation	10,520	11,933	12,622
Corporate [Member]
Adjustment for [Abstract]
Capital expenditures	200	500	1,800
Identifiable assets at year end	19,400	18,300	23,300
Depreciation	1,800	1,400	1,700
Reportable Segment [Member]
Segment Reporting Information [Line Items]
Operating income for reportable segments, excluding impairment expense	90,124	72,950	113,967
Segment Reconciling Items [Member]
Adjustment for [Abstract]
B27 settlement	0	0	7,348
Impairment expense	0	0	68,735
Amortization of intangibles	17,266	18,061	20,621
Corporate and other expense, net	$ 39,368	$ 35,557	$ 45,179