CONDENSED CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016 USD ($) $ / shares shares	Mar. 31, 2015 USD ($) $ / shares shares
Operating Revenues:
Utility	$ 183,669	$ 266,530
Nonutility	149,366	116,422
Total Operating Revenues	333,035	382,952
Cost of Sales - (Excluding depreciation)
- Utility	65,206	144,974
- Nonutility	87,769	96,733
Operations	38,797	41,861
Maintenance	4,384	3,998
Depreciation	20,701	16,819
Energy and Other Taxes	1,925	2,196
Total Operating Expenses	218,782	306,581
Operating Income	114,253	76,371
Other Income and Expense	2,203	2,241
Interest Charges	(9,160)	(8,601)
Income Before Income Taxes	107,296	70,011
Income Taxes	(39,267)	(16,613)
Equity in Earnings of Affiliated Companies	158	455
Income from Continuing Operations	68,187	53,853
Loss from Discontinued Operations - (Net of tax benefit)	(118)	(276)
Net Income	$ 68,069	$ 53,577
Basic Earnings Per Common Share:
Continuing Operations (in dollars per share) | $ / shares	$ 0.96	$ 0.79
Discontinued Operations (in dollars per share) | $ / shares	0.00	0.00
Basic Earnings Per Common Share (in dollars per share) | $ / shares	$ 0.96	$ 0.79
Average Shares of Common Stock Outstanding - Basic (in shares) | shares	71,127	68,397
Diluted Earnings Per Common Share:
Continuing Operations (in dollars per share) | $ / shares	$ 0.95	$ 0.79
Discontinued Operations (in dollars per share) | $ / shares	0.00	0.00
Diluted Earnings Per Common Share (in dollars per share) | $ / shares	$ 0.95	$ 0.79
Average Shares of Common Stock Outstanding - Diluted (in shares) | shares	71,416	68,618
Dividends Declared Per Common Share (in dollars per share) | $ / shares	$ 0.26	$ 0.25