RISK MANAGEMENT AND DERIVATIVE FINANCIAL INSTRUMENTS (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Fair value of derivative financial instruments
Current assets	$ 96
Total derivatives assets	287	2
Current liabilities	3,403	4,769
Non-current liabilities and deferred credits	3,819	5,081
Total derivatives liabilities	7,222	9,850
Non-designated as hedging instruments due to regulatory accounting | Commodity contracts | Gas
Fair value of derivative financial instruments
Current assets	3
Non-current assets and deferred charges- Other	17	2
Current liabilities	104	967
Non-current liabilities and deferred credits		86
Non-designated as hedging instruments due to regulatory accounting | Commodity contracts | Electric
Fair value of derivative financial instruments
Current assets	93
Non-current assets and deferred charges- Other	174
Current liabilities	3,299	3,802
Non-current liabilities and deferred credits	$ 3,819	$ 4,995