Consolidated Statements Of Cash Flow - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash flows from operating activities:
Net income	$ 160,316	$ 195,645
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	115,973	110,515
Deferred income taxes	(10,359)	81
Provision for doubtful accounts	3,622	3,645
Stock-based compensation	5,831	5,331
Gain on sale of other assets	(443)	(598)
Gain on sale of utility system	(403)
Loss on interest rate swap agreements	23,742
Loss on debt extinguishment	18,920
Settlement of interest rate swap agreements	(83,520)
Net change in receivables, inventory and prepayments	(11,657)	(18,058)
Net change in payables, accrued interest, accrued taxes and other accrued liabilities	13,324	4,330
Pension and other postretirement benefits contributions	(8,579)	(12,571)
Other	1,262	2,409
Net cash flows from operating activities	228,029	290,729
Cash flows from investing activities:
Property, plant and equipment additions, including the debt component of allowance for funds used during construction of $3,253 and $2,550	(401,558)	(343,219)
Acquisitions of utility systems, net	(619)	(100,026)
Net proceeds from the sale of other assets	2,361	604
Other	2,296	551
Net cash flows used in investing activities	(397,520)	(442,090)
Cash flows from financing activities:
Customers' advances and contributions in aid of construction	8,692	6,031
Repayments of customers' advances	(2,245)	(2,763)
Net (repayments) proceeds of short-term debt	(5,449)	18,039
Proceeds from long-term debt	1,310,061	402,913
Repayments of long-term debt	(888,951)	(151,571)
Extinguishment of long-term debt	(25,237)
Change in cash overdraft position	(3,882)	(8,661)
Issuance of common stock under dividend reinvestment plan	4,819	1,101
Proceeds from stock issued to finance pending acquisition	1,263,099
Proceeds from tangible equity unit issuance	673,642
Proceeds from exercised stock options	1,735	1,202
Repurchase of common stock	(1,867)	(2,492)
Dividends paid on common stock	(136,821)	(111,766)
Other	(1,164)	(612)
Net cash flows from financing activities	2,196,432	151,421
Net change in cash and cash equivalents	2,026,941	60
Cash and cash equivalents at beginning of period	3,627	4,204
Cash and cash equivalents at end of period	2,030,568	4,264
Non-cash investing activities:
Property, plant and equipment additions purchased at the period end, but not yet paid for	41,059	42,245
Non-cash customer advances and contributions in aid of construction	$ 24,633	$ 14,916