CONSOLIDATED STATEMENTS OF INCOME (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
CONSOLIDATED STATEMENTS OF INCOME [Abstract]
Operating Revenues	$ 359,734	$ 341,925	$ 342,098
Operating Expenses
Purchased Power - affiliates	63,798	60,094	65,329
Purchased Power	93,161	100,680	92,653
Production	10,942	11,752	11,374
Transmission - affiliates	11,151	(3,788)	8,002
Transmission - other	27,012	26,652	23,799
Other operation	56,859	56,642	59,160
Maintenance	37,471	29,851	24,212
Depreciation	19,306	17,570	16,921
Taxes other than income	18,514	17,472	16,727
Income tax expense	5,167	7,545	5,033
Total Operating Expenses	343,381	324,470	323,210
Utility Operating Income	16,353	17,455	18,888
Other Income
Equity in earnings of affiliates	27,733	21,098	17,472
Allowance for equity funds during construction	118	119	161
Other income	2,794	3,243	2,935
Other deductions	(3,021)	(2,284)	(1,585)
Merger-related expenses	(25,977)	0	0
Income tax benefit (expense)	1,356	(7,117)	(5,640)
Total Other Income	3,003	15,059	13,343
Interest Expense
Interest on long-term debt	13,305	11,163	11,139
Other interest	479	458	449
Allowance for borrowed funds during construction	(132)	(61)	(106)
Total Interest Expense	13,652	11,560	11,482
Net Income	5,704	20,954	20,749
Dividends declared on preferred stock	368	368	368
Earnings available for common stock	$ 5,336	$ 20,586	$ 20,381
Per Common Share Data:
Basic earnings per share (in dollars per share)	$ 0.40	$ 1.66	$ 1.75
Diluted earnings per share (in dollars per share)	$ 0.40	$ 1.66	$ 1.74
Average shares of common stock outstanding - basic (in shares)	13,404,909	12,370,486	11,660,170
Average shares of common stock outstanding - diluted (in shares)	13,487,608	12,405,866	11,705,518
Dividends declared per share of common stock (in dollars per share)	$ 0.92	$ 0.92	$ 0.92