Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating revenues:
Operating revenues:	$ 1,227,938	$ 1,197,373
Operating expenses:
Operation and maintenance:	811,659	821,000
Purchased natural gas sold	176,237	165,412
Depreciation, depletion and amortization	73,723	69,239
Taxes, other than income	62,534	64,112
Electric fuel and purchased power	18,621	20,540
Total operating expenses	1,142,774	1,140,303
Operating income	85,164	57,070
Other income (expense)	3,354	(1,005)
Interest expense	23,453	24,553
Income before income taxes	65,065	31,512
Income taxes	12,949	5,973
Income from continuing operations	52,116	25,539
Income (loss) from discontinued operations, net of tax	15	(409)
Net income	$ 52,131	$ 25,130
Earnings per share - basic:
Income from continuing operations	$ 0.26	$ 0.13
Discontinued operations, net of tax	0	0
Earnings per share - basic	0.26	0.13
Earnings per share - diluted:
Income from continuing operations	0.26	0.13
Discontinued operations, net of tax	0	0
Earnings per share - diluted	$ 0.26	$ 0.13
Weighted average common shares outstanding - basic	200,708	200,440
Weighted average common shares outstanding - diluted	200,952	200,456
Regulated operation
Operating revenues:
Operating revenues:	$ 442,381	$ 418,682
Operating expenses:
Operation and maintenance:	94,333	87,608
Income from continuing operations	56,121	51,129
Nonregulated operation
Operating revenues:
Operating revenues:	785,557	778,691
Operating expenses:
Operation and maintenance:	717,326	733,392
Income from continuing operations	$ (4,005)	$ (25,590)