REGULATORY ASSETS & REGULATORY LIABILITIES 2 (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	$ 64,655	$ 41,899
Excess Plant Removal Costs
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	34,701	35,940
Conservation Incentive Program Payable
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	17,255	4,700
Societal Benefit Costs
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	12,699	0
Other Regulatory Liablities
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	$ 0	$ 1,259