Consolidated Statements Of Cash Flow - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash flows from operating activities:
Net income	$ 199,376	$ 183,689
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	78,346	72,944
Deferred income taxes	(19,774)	19,335
Provision for doubtful accounts	5,991	8,921
Stock-based compensation	2,732	2,724
Gain on sale of utility systems and other assets	(19)	(91)
Net change in receivables, inventory and prepayments	49,050	30,261
Net change in payables, accrued interest, accrued taxes and other accrued liabilities	(5,354)	(53,756)
Pension and other postretirement benefits contributions		(6,363)
Other	256	(2,183)
Net cash flows from operating activities	310,604	255,481
Cash flows from investing activities:
Property, plant and equipment additions, including the debt component of allowance for funds used during construction of $1,449 and $170	(183,322)	(178,009)
Acquisitions of utility systems, net	(50,009)
Net proceeds from the sale of other assets	19	100
Other	80	197
Net cash flows used in investing activities	(233,232)	(177,712)
Cash flows from financing activities:
Customers' advances and contributions in aid of construction	2,962	4,716
Repayments of customers' advances	(159)	(971)
Net proceeds (repayments) of short-term debt	14,744	(3,305)
Proceeds from long-term debt	165,000	85,000
Repayments of long-term debt	(67,023)	(46,305)
Change in cash overdraft position	(81,722)	(44,003)
Proceeds from issuance of common stock under dividend reinvestment plan	4,117	4,161
Proceeds from exercised stock options	1,012	714
Repurchase of common stock	(1,012)	(3,262)
Dividends paid on common stock	(67,821)	(61,520)
Other	261	225
Net cash flows from financing activities	(29,641)	(64,550)
Net change in cash and cash equivalents	47,731	13,219
Cash and cash equivalents at beginning of period	10,567	4,827
Cash and cash equivalents at end of period	58,298	18,046
Non-cash investing activities:
Property, plant and equipment additions purchased at the period end, but not yet paid for	74,451	73,014
Non-cash customer advances and contributions in aid of construction	$ 1,829	$ 8,997