Statements of Cash Flows (Unaudited) (Parenthetical) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
CASH FLOWS FROM INVESTING ACTIVITIES:
Utility plant additions, debt portion of allowance for funds used during construction	$ 83	$ 88
Supplemental schedule of non-cash investing and financing activities:
Accounts payable, construction of utility plant	$ 1,017	$ 1,655