CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
CASH FLOW FROM OPERATING ACTIVITIES:
Net income	$ 97,250	$ 118,845	$ 185,607	$ 284,825
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	122,646	93,442	400,245	337,816
Deferred income taxes	32,346	23,326	70,232	48,734
Changes in current assets and liabilities:
Accounts receivable, net of allowances	(44,971)	42,892	(139,417)	(51,717)
Accrued utility revenue	32,900	31,900	(1,500)	(2,400)
Deferred purchased gas costs	(82,248)	(291,469)	(134,507)	(265,385)
Accounts payable	(82,952)	(41,147)	8,621	11,882
Accrued taxes	33,964	34,636	(7,397)	19,430
Other current assets and liabilities	79,680	(5,255)	(4,274)	25,719
Gains on sale of property and equipment	(1,916)	(1,509)	(7,313)	(3,329)
Changes in undistributed stock compensation	4,180	3,658	9,816	7,956
Equity AFUDC	(258)	(981)	723	(4,644)
Changes in deferred charges and other assets	(297)	(10,379)	(3,459)	(49,465)
Changes in other liabilities and deferred credits	(3,704)	(50,416)	(26,917)	(57,365)
Net cash provided by (used in) operating activities	186,620	(52,457)	350,460	302,057
CASH FLOW FROM INVESTING ACTIVITIES:
Construction expenditures and property additions	(162,796)	(152,709)	(725,713)	(767,159)
Acquisition of businesses, net of cash acquired	0	0	(2,354,260)	0
Changes in customer advances	7,693	4,286	19,381	12,885
Other	893	3,563	15,586	8,136
Net cash used in investing activities	(154,210)	(144,860)	(3,045,006)	(746,138)
CASH FLOW FROM FINANCING ACTIVITIES:
Issuance of common stock, net	453,495	48,990	618,146	185,087
Centuri distribution to redeemable noncontrolling interest	(39,649)	0	(39,649)	0
Dividends paid	(35,970)	(32,619)	(141,573)	(128,117)
Issuance of long-term debt, net	709,927	10,659	2,359,964	573,058
Retirement of long-term debt	(143,453)	(21,228)	(574,889)	(302,466)
Change in credit facility and commercial paper	(130,000)	0	(150,000)	0
Change in short-term debt	(435,000)	203,000	(686,000)	153,000
Issuance of short-term debt	0	0	1,850,000	0
Withholding remittance - share-based compensation	(1,978)	(1,242)	(2,000)	(1,242)
Other	(7,898)	(1,353)	(7,274)	(4,505)
Net cash provided by financing activities	369,474	206,207	3,226,725	474,815
Effects of currency translation on cash and cash equivalents	85	103	142	646
Change in cash and cash equivalents	401,969	8,993	532,321	31,380
Cash and cash equivalents at beginning of period	222,697	83,352	92,345	60,965
Cash and cash equivalents at end of period	624,666	92,345	624,666	92,345
SUPPLEMENTAL INFORMATION:
Interest paid, net of amounts capitalized	35,262	8,303	131,311	100,412
Income taxes paid (received), net	$ 1,408	$ 1,651	$ 3,965	$ 10,764