CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
OPERATING ACTIVITIES:
Net Income	$ 120,468	$ 102,286
Items not affecting cash:
Depreciation and depletion	86,600	87,296
Amortization of debt issue costs, discount and deferred hedge gain	2,317	2,333
Stock-based compensation costs	3,597	3,738
Equity portion of allowance for funds used during construction	(2,318)	(1,531)
(Gain) loss on disposition of assets	(176)	11
Deferred income taxes	(16,547)	5,019
Changes in current assets and liabilities:
Accounts receivable	36,348	52,307
Inventories	(966)	5,734
Other current assets	(437)	(2,801)
Accounts payable	(19,683)	(23,849)
Accrued expenses	(20,781)	5,266
Regulatory assets	(13,106)	10,118
Regulatory liabilities	(23,652)	10,325
Other noncurrent assets	(3,059)	(3,908)
Other noncurrent liabilities	(3,992)	(5,217)
Cash Provided by Operating Activities	144,613	247,127
INVESTING ACTIVITIES:
Property, plant, and equipment additions	(147,027)	(116,456)
Acquisitions	0	(18,517)
Cash Used in Investing Activities	(147,027)	(134,973)
FINANCING ACTIVITIES:
Treasury stock activity	999	1,773
Proceeds from issuance of common stock, net	0	44,865
Dividends on common stock	(57,562)	(54,253)
Issuance of long-term debt	50,000	0
Line of credit borrowings, net	7,000	0
Line of credit borrowings	0	1,129,000
Line of credit repayments	0	(913,000)
Repayments of short-term borrowings, net	0	(319,556)
Financing costs	(875)	(100)
Cash Used in Financing Activities	(438)	(111,271)
(Decrease) Increase in Cash, Cash Equivalents, and Restricted Cash	(2,852)	883
Cash, Cash Equivalents, and Restricted Cash, beginning of period	15,311	12,029
Cash, Cash Equivalents, and Restricted Cash, end of period	12,459	12,912
Cash paid during the period for:
Income taxes	68	55
Interest	42,100	38,890
Significant non-cash transactions:
Capital expenditures included in accounts payable	$ 13,543	$ 11,266