STOCK-BASED COMPENSATION (Details 3) - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Unvested, Shares, Outstanding, Beginning of period	63	63	63
Unvested Shares, Granted	50	38	28
Unvested Shares, Vested	(28)	(30)	(23)
Unvested Shares, Forfeited	0	(8)	(5)
Unvested Shares, Outstanding, End of period	86	63	63	63
Weighted Average Grant Date Fair Value, Outstanding, Beginning of period	$ 45.72	$ 42.72	$ 19.34
Weighted Average Grant Date Fair Value, Granted	49.51	40.59	67.26
Weighted Average Grant Date Fair Value, Vested	44.49	33.89	15.82
Weighted Average Grant Date Fair Value, Forfeited	0	46.05	19.41
Weighted Average Grant Date Fair Value, Outstanding, End of period	$ 48.34	$ 45.72	$ 42.72	$ 19.34
Weighted Average Remaining Term (years)	2 years 7 months 6 days	2 years 2 months 12 days	2 years 2 months 12 days	2 years 7 months 6 days