Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Operating revenues:
Operating revenues:	$ 1,362,928	$ 1,303,573	$ 2,560,302	$ 2,394,764
Operating expenses:
Operation and maintenance:	1,029,171	1,021,031	1,850,171	1,723,945
Purchased natural gas sold	56,844	54,866	222,256	238,695
Depreciation, depletion and amortization	71,508	63,019	140,747	122,916
Taxes, other than income	52,584	47,953	116,696	101,982
Electric fuel and purchased power	14,567	19,393	35,107	45,696
Total operating expenses	1,224,674	1,206,262	2,364,977	2,233,234
Operating income	138,254	97,311	195,325	161,530
Other income	10,063	1,615	9,058	9,208
Interest expense	24,818	25,429	49,371	48,836
Income before income taxes	123,499	73,497	155,012	121,902
Income taxes	23,657	10,352	29,631	17,668
Income from continuing operations	99,842	63,145	125,381	104,234
Loss from discontinued operations, net of tax	(139)	(1,320)	(548)	(1,483)
Net income	$ 99,703	$ 61,825	$ 124,833	$ 102,751
Earnings per share - basic:
Income from continuing operations	$ 0.50	$ 0.32	$ 0.62	$ 0.53
Discontinued operations, net of tax	0	(0.01)	0	(0.01)
Earnings per share - basic	0.50	0.31	0.62	0.52
Earnings per share - diluted:
Income from continuing operations	0.50	0.32	0.62	0.53
Discontinued operations, net of tax	0	(0.01)	0	(0.01)
Earnings per share - diluted	$ 0.50	$ 0.31	$ 0.62	$ 0.52
Weighted average common shares outstanding - basic	200,522	198,270	200,481	197,341
Weighted average common shares outstanding - diluted	200,539	198,287	200,497	197,356
Regulated operation
Operating revenues:
Operating revenues:	$ 241,353	$ 236,247	$ 660,035	$ 675,864
Operating expenses:
Operation and maintenance:	83,103	88,415	170,712	176,186
Income from continuing operations	19,878	7,597	71,007	66,606
Nonregulated operation
Operating revenues:
Operating revenues:	1,121,575	1,067,326	1,900,267	1,718,900
Operating expenses:
Operation and maintenance:	946,068	932,616	1,679,459	1,547,759
Income from continuing operations	$ 79,964	$ 55,548	$ 54,374	$ 37,628