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
Revenues
Electric	$ 797,562	$ 790,701	$ 781,186
Gas	318,335	318,735	353,977
Other	1,419	1,284	6,747
Total Revenues	1,117,316	1,110,720	1,141,910
Operating Expenses
Cost of sales	494,559	531,089	573,686
Operating, general and administrative	267,160	237,047	245,618
Property and other taxes	89,122	88,198	79,582
Depreciation	100,926	91,769	89,039
Total Operating Expenses	951,767	948,103	987,925
Operating Income	165,549	162,617	153,985
Interest Expense	(66,859)	(65,826)	(67,760)
Other Income	3,931	6,345	2,499
Income Before Income Taxes	102,621	103,136	88,724
Income Tax Expense	(10,065)	(25,760)	(15,304)
Net Income	$ 92,556	$ 77,376	$ 73,420
Average Common Shares Outstanding	36,258,463	36,190,373	36,091,362
Basic Earnings per Average Common Share	$ 2.55	$ 2.14	$ 2.03
Diluted Earnings per Average Common Share	$ 2.53	$ 2.14	$ 2.02
Dividends Declared per Average Common Share	$ 1.44	$ 1.36	$ 1.34