CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Revenues
Electric	$ 219,659	$ 209,755	$ 492,696	$ 448,097
Gas	51,060	52,062	162,243	155,222
Total Revenues	270,719	261,817	654,939	603,319
Operating Expenses
Cost of sales	55,744	32,190	171,479	128,267
Operating, general and administrative	80,826	73,834	161,918	148,179
Property and other taxes	44,310	43,042	89,099	85,855
Depreciation and depletion	41,016	43,541	86,600	87,296
Total Operating Expenses	221,896	192,607	509,096	449,597
Operating Income	48,823	69,210	145,843	153,722
Interest Expense, net	(23,511)	(23,197)	(47,301)	(46,167)
Other Income (Expense), net	124	876	1,273	(253)
Income Before Income Taxes	25,436	46,889	99,815	107,302
Income Tax Benefit (Expense)	22,226	(3,102)	20,653	(5,016)
Net Income	$ 47,662	$ 43,787	$ 120,468	$ 102,286
Average Common Shares Outstanding	50,440,685	49,869,176	50,410,928	49,643,954
Basic Earnings per Average Common Share	$ 0.94	$ 0.88	$ 2.39	$ 2.06
Diluted Earnings per Average Common Share	0.94	0.87	2.38	2.05
Dividends Declared per Common Share	$ 0.575	$ 0.550	$ 1.150	$ 1.100