REGULATORY ASSETS & REGULATORY LIABILITIES 2 (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	$ 60,615	$ 56,517
Excess Plant Removal Costs [Member]
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	42,673	45,593
Deferred Revenues - Net [Member]
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	14,693	10,924
Other Regulatory Liablities [Member]
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	$ 3,249	$ 0