CONDENSED STATEMENTS OF INCOME (UNAUDITED) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Income Statement [Abstract]
Operating Revenues	$ 59,674	$ 54,251	$ 300,308	$ 292,864
Operating Expenses:
Cost of Sales (Excluding depreciation)	24,717	21,053	128,427	127,959
Operations	18,613	17,536	62,132	56,677
Maintenance	3,353	3,570	10,140	10,133
Depreciation	8,654	7,975	25,128	23,010
Energy and Other Taxes	1,052	1,167	5,332	5,815
Total Operating Expenses	56,389	51,301	231,159	223,594
Operating Income	3,285	2,950	69,149	69,270
Other Income and Expense	764	1,703	3,024	4,482
Interest Charges	(2,629)	(3,872)	(8,379)	(11,832)
Income Before Income Taxes	1,420	781	63,794	61,920
Income Taxes	(471)	(258)	(23,511)	(23,122)
Net Income	$ 949	$ 523	$ 40,283	$ 38,798