STOCK-BASED COMPENSATION Stock options activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Roll Forward]
Stock options outstanding - remaining contractual term	1 year 10 months 6 days	2 years 4 months 6 days
Stock options exercisable - remaining contractual term	1 year 10 months 6 days	2 years 4 months 6 days
Stock options outstanding	$ 0	$ 0
Stock options exercisable	$ 0	$ 0
Stock options
Share-based Compensation Arrangement by Share-based Payment Award, Outstanding, Weighted Average Exercise Price [Roll Forward]
Options outstanding at January 1, weighted average exercise price per share	$ 6.16	$ 8.13	$ 8.78
Granted, weighted average exercise price per share	0.00	0.00	2.49
Forfeited, weighted average exercise price per share	0.00	0.00	7.32
Expired, weighted average exercise price per share	15.97	11.09	13.35
Options outstanding at December 31, weighted average exercise price per share	3.86	6.16	8.13
Options exercisable at December 31, weighted average exercise price per share	$ 3.86	$ 6.16	$ 8.91
Share-based Compensation Arrangement by Share-based Payment Award [Roll Forward]
Options outstanding at January 1, number of options outstanding	123,500	206,000	756,800
Granted, number of options outstanding	0	0	50,000
Forfeited, number of options outstanding	0	0	(485,000)
Expired, number of options outstanding	(23,500)	(82,500)	(115,800)
Options outstanding at December 31, number of options outstanding	100,000	123,500	206,000
Options exercisable at December 31, number of options outstanding	100,000	123,500	181,000