Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021	Jun. 30, 2021
Current assets:
Cash and cash equivalents	$ 65,394	$ 54,161	$ 57,946
Receivables, net	1,184,116	946,741	903,831
Inventories	401,433	335,609	316,328
Current regulatory assets	102,535	118,691	109,581
Prepayments and other current assets	105,753	95,741	74,259
Total current assets	1,859,231	1,550,943	1,461,945
Noncurrent assets:
Property, plant and equipment	9,099,752	8,972,849	8,417,559
Less accumulated depreciation, depletion and amortization	3,210,940	3,216,461	3,129,717
Net property, plant and equipment	5,888,812	5,756,388	5,287,842
Goodwill	763,262	765,386	717,863
Other intangible assets, net	20,040	22,578	23,401
Regulatory assets	347,061	357,851	376,913
Investments	161,247	175,476	173,157
Operating lease right-of-use assets	115,802	124,138	112,437
Other	173,670	157,675	144,653
Total noncurrent assets	7,469,894	7,359,492	6,836,266
Total assets	9,329,125	8,910,435	8,298,211
Current liabilities:
Short-term borrowings	100,000	0	50,000
Long-term debt due within one year	214,453	148,053	1,549
Accounts payable	579,064	478,933	431,878
Taxes payable	84,970	80,372	78,805
Dividends payable	44,229	44,229	42,791
Accrued compensation	98,159	81,904	95,909
Operating lease liabilities due within one year	33,626	35,368	31,787
Regulatory liabilities due within one year	17,884	16,303	23,454
Other accrued liabilities	208,290	207,078	188,187
Total current liabilities	1,380,675	1,092,240	944,360
Noncurrent liabilities:
Long-term debt	2,713,514	2,593,847	2,335,500
Deferred income taxes	597,733	591,962	538,633
Asset retirement obligations	467,995	458,061	450,620
Regulatory liabilities	433,019	428,790	428,467
Operating lease liabilities	82,891	89,253	81,052
Other	266,488	273,408	320,777
Total noncurrent liabilities	4,561,640	4,435,321	4,155,049
Commitments and contingencies
Stockholders' equity:
Common stock	203,889	203,889	202,822
Other paid-in capital	1,454,131	1,461,205	1,422,169
Retained earnings	1,775,947	1,762,410	1,624,405
Accumulated other comprehensive loss	(43,531)	(41,004)	(46,968)
Treasury stock at cost - 538,921 shares	(3,626)	(3,626)	(3,626)
Total stockholders' equity	3,386,810	3,382,874	3,198,802
Total liabilities and stockholders' equity	$ 9,329,125	$ 8,910,435	$ 8,298,211
Common Stock, Shares Authorized	500,000,000	500,000,000	500,000,000
Common Stock, Par or Stated Value Per Share	$ 1.00	$ 1.00	$ 1.00
Common Stock, Shares, Issued	203,889,661	203,889,661	202,822,301
Treasury Stock, Common, Shares	538,921	538,921	538,921