FINANCIAL INSTRUMENTS Schedule of Other Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost	$ 115,985	$ 145,089
Unrealized gains	23,180	11,000
Unrealized losses	0	(26)
Fair value	139,165	156,063
Commodities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost	101,184	130,671
Unrealized gains	18,165	6,625
Unrealized losses	0	0
Fair value	119,349	137,296
Private and unlisted equity securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost	14,801	14,418
Unrealized gains	5,015	4,375
Unrealized losses	0	(26)
Fair value	$ 19,816	$ 18,767