DERIVATIVE INSTRUMENTS 3 (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014
Commodity Contract
Offsetting Derivative Assets [Abstract]
Gross amounts of recognized assets/liabilities	$ 1		$ 2,051
Gross amount offset in the balance sheet	0		0
Net amounts of assets/liabilities in balance sheet	1		2,051
Gross amounts not offset in the balance sheet, Financial Instruments	(1)	[1]	(2)	[1]
Gross amounts not offset in the balance sheet, Cash Collateral Posted	0		0
Net amount	0		2,049
Offsetting Derivative Liabilities [Abstract]
Gross amounts of recognized assets/liabilities	(6,797)		(7,603)
Gross amount offset in the balance sheet	0		0
Net amounts of assets/liabilities in balance sheet	(6,797)		(7,603)
Gross amounts not offset in the balance sheet, Financial Instruments	1	[2]	2	[2]
Gross amounts not offset in the balance sheet, Cash Collateral Posted	6,506		7,253
Net amount	(290)		(348)
Interest Rate Contract
Offsetting Derivative Liabilities [Abstract]
Gross amounts of recognized assets/liabilities	(8,330)		(7,325)
Gross amount offset in the balance sheet	0		0
Net amounts of assets/liabilities in balance sheet	(8,330)		(7,325)
Gross amounts not offset in the balance sheet, Financial Instruments	0		0
Gross amounts not offset in the balance sheet, Cash Collateral Posted	0		0
Net amount	$ (8,330)		$ (7,325)

[1] The balances at March 31, 2015 and December 31, 2014 were related to derivative liabilities which can be net settled against derivative assets.

[2] The balances at March 31, 2015 and December 31, 2014 were related to derivative assets which can be net settled against derivative liabilities.