CONDENSED CONSOLIDATED STATEMENTS OF INCOME (unaudited) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
CONDENSED CONSOLIDATED STATEMENTS OF INCOME [Abstract]
Operating Revenues	$ 96,242	$ 97,085
Operating Expenses
Purchased Power - affiliates	15,565	17,411
Purchased Power	24,923	23,941
Production	2,576	3,144
Transmission - affiliates	3,888	2,257
Transmission - other	7,455	7,104
Other operation	15,030	18,594
Maintenance	6,280	5,707
Depreciation	4,346	4,485
Taxes other than income	5,296	4,657
Income tax expense	3,138	2,857
Total Operating Expenses	88,497	90,157
Utility Operating Income	7,745	6,928
Other Income
Equity in earnings of affiliates	6,800	6,941
Allowance for equity funds during construction	80	56
Other income	726	703
Other deductions	(434)	(654)
Merger-related expenses	(242)	0
Income tax expense	(2,220)	(2,302)
Total Other Income	4,710	4,744
Interest Expense
Interest on long-term debt	3,502	3,144
Other interest	122	129
Allowance for borrowed funds during construction	(44)	(26)
Total Interest Expense	3,580	3,247
Net Income	8,875	8,425
Dividends declared on preferred stock	92	92
Earnings available for common stock	$ 8,783	$ 8,333
Per Common Share Data:
Basic earnings per share (in dollars per share)	$ 0.65	$ 0.62
Diluted earnings per share (in dollars per share)	$ 0.65	$ 0.62
Average shares of common stock outstanding - basic (in shares)	13,491,377	13,353,973
Average shares of common stock outstanding - diluted (in shares)	13,570,720	13,406,926
Dividends declared per share of common stock (in dollars per share)	$ 0.23	$ 0.46