CONDENSED CONSOLIDATED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Revenues
Electric	$ 207,055	$ 208,622
Gas	101,746	129,212
Other	299	426
Total Revenues	309,100	338,260
Operating Expenses
Cost of sales	138,396	162,071
Operating, general and administrative	65,573	67,383
Property and other taxes	23,665	25,396
Depreciation	26,433	25,315
Total Operating Expenses	254,067	280,165
Operating Income	55,033	58,095
Interest Expense, net	(15,962)	(17,147)
Other Income	984	805
Income Before Income Taxes	40,055	41,753
Income Tax Expense	(8,012)	(9,178)
Net Income	32,043	32,575
Other comprehensive (loss) income, net of tax:
Reclassification of net gains on derivative instruments	(183)	(297)
Postretirement medical liability adjustment	205	0
Foreign currency translation	(47)	51
Total Other Comprehensive Loss	(25)	(246)
Comprehensive Income	$ 32,018	$ 32,329
Average Common Shares Outstanding	36,328,360	36,241,904
Basic Earnings per Average Common Share	$ 0.88	$ 0.90
Diluted Earnings per Average Common Share	$ 0.88	$ 0.89
Dividends Declared per Average Common Share	$ 0.37	$ 0.36