Business Segment Data (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014 N	Mar. 31, 2013	Dec. 31, 2013
Segment Reporting Information [Line Items]
Number of Reportable Segments	2
Operating Revenues	$ 27,173	$ 27,038
Operating Income	5,967	5,865
Net Income	3,169	3,177
Capital Expenditures	4,165	4,506
Assets	530,856		530,341
Regulated [Member]
Segment Reporting Information [Line Items]
Operating Revenues	23,653	23,424
Operating Income	5,404	5,338
Net Income	2,881	2,910
Capital Expenditures	4,134	4,401
Assets	529,756		529,381
Non - Regulated [Member]
Segment Reporting Information [Line Items]
Operating Revenues	3,637	3,736
Operating Income	563	527
Net Income	288	267
Capital Expenditures	31	105
Assets	9,033		8,887
Inter-segment Elimination [Member]
Segment Reporting Information [Line Items]
Operating Revenues	(117)	(122)
Assets	$ (7,933)		$ (7,927)