REGULATORY MATTERS Net Changes in Regulatory Assets and Liabilities (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2016 USD ($)
Revenue Accruals and Deferrals
Beginning balance	$ (2,564)
Net refund of 2014 revenue deferrals and accruals, including accrued interest	11,190
Net revenue accrual for the six months ended June 30, 2016	7,206
Net accrued interest payable for the six months ended June 30, 2016	(405)
Ending balance	$ 15,427