Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating revenues:
Operating revenues:	$ 1,091,191	$ 976,293
Operating expenses:
Operation and maintenance:	702,914	600,856
Purchased natural gas sold	183,829	181,967
Depreciation, depletion and amortization	59,897	52,729
Taxes, other than income	54,029	48,854
Electric fuel and purchased power	26,304	22,511
Total operating expenses	1,026,973	906,917
Operating income	64,218	69,376
Other income	7,595	582
Interest expense	23,407	20,447
Income before income taxes	48,406	49,511
Income taxes	7,317	7,551
Income from continuing operations	41,089	41,960
Income (loss) from discontinued operations, net of tax (Note 10)	(163)	477
Net income	$ 40,926	$ 42,437
Earnings per share - basic:
Income from continuing operations	$ 0.21	$ 0.22
Discontinued operations, net of tax	0	0
Earnings per share - basic	0.21	0.22
Earnings per share - diluted:
Income from continuing operations	0.21	0.22
Discontinued operations, net of tax	0	0
Earnings per share - diluted	$ 0.21	$ 0.22
Weighted average common shares outstanding - basic	196,401	195,304
Weighted average common shares outstanding - diluted	196,414	195,982
Regulated operation
Operating revenues:
Operating revenues:	$ 439,617	$ 424,459
Operating expenses:
Operation and maintenance:	87,770	86,112
Income from continuing operations	59,009	51,166
Nonregulated operation
Operating revenues:
Operating revenues:	651,574	551,834
Operating expenses:
Operation and maintenance:	615,144	514,744
Income from continuing operations	$ (17,920)	$ (9,206)