Statements of Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statements of Income (Unaudited) [Abstract]
OPERATING REVENUES	$ 12,698	$ 12,692	$ 36,368	$ 36,236
OPERATING EXPENSES:
Operation and maintenance	2,280	2,362	7,197	6,650
Administrative and general	1,944	1,931	6,193	6,203
Depreciation and amortization	1,770	1,697	5,235	5,064
Taxes other than income taxes	275	250	856	871
Operating expenses	6,269	6,240	19,481	18,788
Operating income	6,429	6,452	16,887	17,448
OTHER INCOME (EXPENSES):
Interest on debt	(1,377)	(1,346)	(4,117)	(3,988)
Allowance for funds used during construction	53	311	176	630
Other pension costs	(322)	(305)	(964)	(915)
Other income (expenses), net	(54)	(73)	(213)	(293)
Other income (expenses)	(1,700)	(1,413)	(5,118)	(4,566)
Income before income taxes	4,729	5,039	11,769	12,882
Income taxes	929	1,108	2,070	3,435
Net Income	$ 3,800	$ 3,931	$ 9,699	$ 9,447
Basic Earnings Per Share (in dollars per share)	$ 0.29	$ 0.31	$ 0.75	$ 0.74
Diluted Earnings Per Share (in dollars per share)	0.29	0.31	0.75	0.74
Cash Dividends Declared Per Share (in dollars per share)	$ 0.1666	$ 0.1602	$ 0.4998	$ 0.4806