FINANCIAL INSTRUMENTS Schedule of Fair Value of Financial Contracts Outstanding (Details) - USD ($) $ in Thousands	Sep. 30, 2017		Dec. 31, 2016
Derivative [Line Items]
Financial contracts receivable	$ 20,644		$ 76,381
Financial contracts payable	(10,409)		(2,237)
Financial contracts receivable
Derivative [Line Items]
Financial contracts receivable	20,644		76,381
Financial contracts payable
Derivative [Line Items]
Financial contracts payable	(10,409)		(2,237)
Call options | Financial contracts receivable
Derivative [Line Items]
Financial contracts receivable, Notional amount of underlying instruments	14,008		134,495
Financial contracts receivable	887		26,508
Commodity Swaps | Financial contracts receivable
Derivative [Line Items]
Financial contracts receivable, Notional amount of underlying instruments	34,190		82,009
Financial contracts receivable	2,392		13,506
Commodity Swaps | Financial contracts payable
Derivative [Line Items]
Financial contracts payable, Notional amount of underlying instruments	17,833
Financial contracts payable	(104)
Interest rate swaps | Financial contracts receivable
Derivative [Line Items]
Financial contracts receivable, Notional amount of underlying instruments	21,286		20,490
Financial contracts receivable	302		218
Forwards | Financial contracts payable
Derivative [Line Items]
Financial contracts payable, Notional amount of underlying instruments	12,611		6,880
Financial contracts payable	(124)		(118)
Futures | Financial contracts payable
Derivative [Line Items]
Financial contracts payable, Notional amount of underlying instruments	5,773
Financial contracts payable	(34)
Put options (2) | Financial contracts receivable
Derivative [Line Items]
Financial contracts receivable, Notional amount of underlying instruments	1,363	[1]	115,481	[2]
Financial contracts receivable	8	[1]	6,703	[2]
Put options (2) | Financial contracts payable
Derivative [Line Items]
Financial contracts payable, Notional amount of underlying instruments	253		815
Financial contracts payable	(42)		(172)
Total return swaps – equities | Financial contracts receivable
Derivative [Line Items]
Financial contracts receivable, Notional amount of underlying instruments	46,686		100,199
Financial contracts receivable	17,037		29,413
Total return swaps – equities | Financial contracts payable
Derivative [Line Items]
Financial contracts payable, Notional amount of underlying instruments	57,616		31,257
Financial contracts payable	(10,105)		(1,947)
Warrants and rights on listed equities | Financial contracts receivable
Derivative [Line Items]
Financial contracts receivable, Notional amount of underlying instruments	52		67
Financial contracts receivable	18		33
NO MARKET (E.G. UNLISTED) [Member] | Call options | Financial contracts receivable
Derivative [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Asset, at Fair Value	300		22,400
NO MARKET (E.G. UNLISTED) [Member] | Put options (2) | Financial contracts receivable
Derivative [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Asset, at Fair Value	0		6,700
NO MARKET (E.G. UNLISTED) [Member] | Put options (2) | Financial contracts payable
Derivative [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Liability, at Fair Value	$ 0		$ (200)

[1] Includes options on the Chinese Yuan, denominated in U.S. dollars.

[2] Includes options on the Japanese Yen and the Chinese Yuan, denominated in U.S. dollars.