CONSOLIDATED STATEMENTS OF INCOME (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Statement [Abstract]
Operating Revenues	$ 110,379	$ 102,069	$ 102,735
Operating Expenses:
Operations and Maintenance	60,458	56,634	55,481
Depreciation	10,409	9,746	9,244
Other Taxes	11,865	11,488	11,413
Total Operating Expenses	82,732	77,868	76,138
Operating Income	27,647	24,201	26,597
Other Income (Expense):
Allowance for Funds Used During Construction	484	821	970
Other Income	517	1,523	912
Other Expense	(144)	(195)	(438)
Total Other Income, net	857	2,149	1,444
Interest Charges	6,725	6,376	6,925
Income before Income Taxes	21,779	19,974	21,116
Income Taxes	7,383	6,527	6,786
Net Income	14,396	13,447	14,330
Preferred Stock Dividend Requirements	206	206	207
Earnings Applicable to Common Stock	$ 14,190	$ 13,241	$ 14,123
Earnings per share of Common Stock:
Basic	$ 0.90	$ 0.85	$ 0.96
Diluted	$ 0.90	$ 0.84	$ 0.96
Average Number of Common Shares Outstanding:
Basic	15,733,000	15,615,000	14,654,000
Diluted	15,995,000	15,877,000	14,916,000
Cash Dividends Paid per Common Share	$ 0.743	$ 0.733	$ 0.723