FINANCIAL INSTRUMENTS Schedule of Maturity Distribution of Debt Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Financial Instruments [Abstract]
Trading, debt maturities, within one year, cost	$ 7,557	$ 0
Trading, debt maturities, within one year, fair value	441	0
Trading, debt maturities, 1 to 5 years, Cost	0	17,803
Trading, debt maturities, 1 to 5 years, fair value	0	19,492
Trading, debt maturities, 5 to 10 years, Cost	2,109	4,649
Trading, debt maturities, 5 to 10 years, fair value	52	2,327
Trading, debt maturities, after 10 years, Cost	6,782	951
Trading, debt maturities, after 10 years, fair value	6,687	654
Cost/ amortized cost	16,448	23,403
Debt instruments, trading, at fair value	$ 7,180	$ 22,473