Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021	Sep. 30, 2021
Current assets:
Cash and cash equivalents	$ 74,620	$ 54,161	$ 57,241
Receivables, net	1,298,019	946,741	979,862
Inventories	398,642	335,609	312,285
Current regulatory assets	148,160	118,691	133,135
Prepayments and other current assets	104,850	95,741	83,364
Total current assets	2,024,291	1,550,943	1,565,887
Noncurrent assets:
Property, plant and equipment	9,257,067	8,972,849	8,634,737
Less accumulated depreciation, depletion and amortization	3,263,217	3,216,461	3,175,756
Net property, plant and equipment	5,993,850	5,756,388	5,458,981
Goodwill	763,262	765,386	717,646
Other intangible assets, net	18,745	22,578	22,241
Regulatory assets	344,442	357,851	379,245
Investments	157,860	175,476	171,859
Operating lease right-of-use assets	119,586	124,138	109,439
Other	185,094	157,675	143,565
Total noncurrent assets	7,582,839	7,359,492	7,002,976
Total assets	9,607,130	8,910,435	8,568,863
Current liabilities:
Short-term borrowings	100,000	0	50,000
Long-term debt due within one year	214,453	148,053	1,548
Accounts payable	630,699	478,933	525,704
Taxes payable	93,565	80,372	87,455
Dividends payable	44,229	44,229	43,212
Accrued compensation	99,824	81,904	105,867
Operating lease liabilities due within one year	34,569	35,368	30,502
Regulatory liabilities due within one year	18,599	16,303	16,491
Other accrued liabilities	232,364	207,078	212,140
Total current liabilities	1,468,302	1,092,240	1,072,919
Noncurrent liabilities:
Long-term debt	2,773,999	2,593,847	2,326,718
Deferred income taxes	617,996	591,962	557,582
Asset retirement obligations	472,931	458,061	455,522
Regulatory liabilities	433,212	428,790	426,141
Operating lease liabilities	85,884	89,253	79,397
Other	262,948	273,408	318,306
Total noncurrent liabilities	4,646,970	4,435,321	4,163,666
Commitments and contingencies
Stockholders' equity:
Common stock	203,889	203,889	203,889
Other paid-in capital	1,455,241	1,461,205	1,458,208
Retained earnings	1,879,600	1,762,410	1,720,232
Accumulated other comprehensive loss	(43,246)	(41,004)	(46,425)
Treasury stock at cost - 538,921 shares	(3,626)	(3,626)	(3,626)
Total stockholders' equity	3,491,858	3,382,874	3,332,278
Total liabilities and stockholders' equity	$ 9,607,130	$ 8,910,435	$ 8,568,863
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	203,889,661
Treasury Stock, Common, Shares	538,921	538,921	538,921